Nalin Thakker | The University of Manchester (original) (raw)

Papers by Nalin Thakker

Research paper thumbnail of Evaluation of a new binary system of grading oral epithelial dysplasia for prediction of malignant transformation

The aim of this paper is to assess the reproducibility of a novel binary grading system (high/low... more The aim of this paper is to assess the reproducibility of a novel binary grading system (high/low risk) of oral epithelial dysplasia and to compare it with the WHO classification 2005. The accuracy of the new system for predicting malignant transformation was also assessed. Ninety-six consecutive oral epithelial dysplasia biopsies with known clinical outcomes were retrieved from the Oral Pathology archives. A pilot study was conducted on 28 cases to determine the process of classification. Four observers then reviewed the same set of H&E stained slides of 68 oral dysplastic lesions using the two grading systems blinded to the clinical outcomes. The overall inter-observer unweighted and weighted kappa agreements for the WHO grading system were Ks = 0.22 (95% CI: 0.11-0.35), Kw = 0.63 (95% CI: 0.42-0.78), respectively, versus K = 0.50 (95% CI: 0.35-0.67) for the new binary system. Interestingly, all pathologists showed satisfactory agreement on the distinction of mild dysplasia from severe dysplasia and from carcinoma in situ using the new WHO classification. However, assessment of moderate dysplasia remains problematic. The sensitivity and specificity of the new binary grading system for predicting malignant transformation in oral epithelial dysplasia were 85% and 80%, respectively and the accuracy was 82%. The new binary grading system complemented the WHO Classification 2005 and may have merit in helping clinicians to make critical clinical decisions particularly for the cases of moderate dysplasia. Histological grading of dysplasia using established criteria is a reproducible prognosticator in oral epithelial dysplasia. Furthermore, the present study showed that more consensus scoring on either the degree of dysplasia, assessment of risk or the presence of each morphological characteristic by a panel should be encouraged.

Research paper thumbnail of Mutation analysis of the cathepsin C gene in Indian families with Papillon-Lefèvre syndrome

Background: PLS is a rare autosomal recessive disorder characterized by early onset periodontopat... more Background: PLS is a rare autosomal recessive disorder characterized by early onset periodontopathia and palmar plantar keratosis. PLS is caused by mutations in the cathepsin C (CTSC) gene. Dipeptidyl-peptidase I encoded by the CTSC gene removes dipeptides from the aminoterminus of protein substrates and mainly plays an immune and inflammatory role. Several mutations have been reported in this gene in patients from several ethnic groups. We report here mutation analysis of the CTSC gene in three Indian families with PLS.

Research paper thumbnail of Tumor Epression of Major Vault Protein is an Adverse Prognostic Factor for Radiotherapy Outcome in Oropharyngeal Carcinoma

Purpose: Vaults are multi-subunit structures that may be involved in nucleo-cytoplasmic transport... more Purpose: Vaults are multi-subunit structures that may be involved in nucleo-cytoplasmic transport, with the major vault protein (MVP or lung resistance-related protein [LRP]) being the main component. The MVP gene is located on chromosome 16 close to the multidrug resistance-associated protein and protein kinase c-␤ genes. The role of MVP in cancer drug resistance has been demonstrated in various cell lines as well as in ovarian carcinomas and acute myeloid leukemia, but nothing is known about its possible role in radiation resistance. Our aim was to examine this in head-and-neck squamous cell carcinoma (HNSCC). Methods and Materials: Archived biopsy material was obtained for 78 patients with squamous cell carcinoma of the oropharynx who received primary radiotherapy with curative intent. Immunohistochemistry was used to detect MVP expression. Locoregional failure and cancer-specific survival were estimated using cumulative incidence and Cox multivariate analyses. Results: In a univariate and multivariate analysis, MVP expression was strongly associated with both locoregional failure and cancer-specific survival. After adjustment for disease site, stage, grade, anemia, smoking, alcohol, gender, and age, the estimated hazard ratio for high MVP (2/3) compared with low (0/1) was 4.98 (95% confidence interval, 2.17-11.42; p ‫؍‬ 0.0002) for locoregional failure and 4.28 (95% confidence interval, 1.85-9.95; p ‫؍‬ 0.001) for cancer-specific mortality. Conclusion: These data are the first to show that MVP may be a useful prognostic marker associated with radiotherapy resistance in a subgroup of patients with HNSCC.

Research paper thumbnail of Mutation analysis of the cathepsin C gene in Indian families with Papillon-Lefèvre syndrome

BMC medical genetics, Jan 12, 2003

PLS is a rare autosomal recessive disorder characterized by early onset periodontopathia and palm... more PLS is a rare autosomal recessive disorder characterized by early onset periodontopathia and palmar plantar keratosis. PLS is caused by mutations in the cathepsin C (CTSC) gene. Dipeptidyl-peptidase I encoded by the CTSC gene removes dipeptides from the amino-terminus of protein substrates and mainly plays an immune and inflammatory role. Several mutations have been reported in this gene in patients from several ethnic groups. We report here mutation analysis of the CTSC gene in three Indian families with PLS. Peripheral blood samples were obtained from individuals belonging to three Indian families with PLS for genomic DNA isolation. Exon-specific intronic primers were used to amplify DNA samples from individuals. PCR products were subsequently sequenced to detect mutations. PCR-SCCP and ASOH analyses were used to determine if mutations were present in normal control individuals. All patients from three families had a classic PLS phenotype, which included palmoplantar keratosis and...

Research paper thumbnail of Using Prior Information from the Medical Literature in GWAS of Oral Cancer Identifies Novel Susceptibility Variant on Chromosome 4 - the AdAPT Method

PloS one, 2012

Genome-wide association studies (GWAS) require large sample sizes to obtain adequate statistical ... more Genome-wide association studies (GWAS) require large sample sizes to obtain adequate statistical power, but it may be possible to increase the power by incorporating complementary data. In this study we investigated the feasibility of automatically retrieving information from the medical literature and leveraging this information in GWAS.

Research paper thumbnail of Evaluation of a new binary system of grading oral epithelial dysplasia for prediction of malignant transformation

Oral Oncology, 2006

The aim of this paper is to assess the reproducibility of a novel binary grading system (high/low... more The aim of this paper is to assess the reproducibility of a novel binary grading system (high/low risk) of oral epithelial dysplasia and to compare it with the WHO classification 2005. The accuracy of the new system for predicting malignant transformation was also assessed. Ninety-six consecutive oral epithelial dysplasia biopsies with known clinical outcomes were retrieved from the Oral Pathology archives. A pilot study was conducted on 28 cases to determine the process of classification. Four observers then reviewed the same set of H&E stained slides of 68 oral dysplastic lesions using the two grading systems blinded to the clinical outcomes. The overall inter-observer unweighted and weighted kappa agreements for the WHO grading system were Ks = 0.22 (95% CI: 0.11-0.35), Kw = 0.63 (95% CI: 0.42-0.78), respectively, versus K = 0.50 (95% CI: 0.35-0.67) for the new binary system. Interestingly, all pathologists showed satisfactory agreement on the distinction of mild dysplasia from severe dysplasia and from carcinoma in situ using the new WHO classification. However, assessment of moderate dysplasia remains problematic. The sensitivity and specificity of the new binary grading system for predicting malignant transformation in oral epithelial dysplasia were 85% and 80%, respectively and the accuracy was 82%. The new binary grading system complemented the WHO Classification 2005 and may have merit in helping clinicians to make critical clinical decisions particularly for the cases of moderate dysplasia. Histological grading of dysplasia using established criteria is a reproducible prognosticator in oral epithelial dysplasia. Furthermore, the present study showed that more consensus scoring on either the degree of dysplasia, assessment of risk or the presence of each morphological characteristic by a panel should be encouraged.

Research paper thumbnail of Why oral histopathology suffers inter-observer variability on grading oral epithelial dysplasia: An attempt to understand the sources of variation

Oral Oncology, 2007

The present study attempted to assess the reasons behind the inter-observer variation in grading ... more The present study attempted to assess the reasons behind the inter-observer variation in grading oral epithelial dysplasia (OED). Three oral pathologists and one general pathologist examined 68 histological slides of OED lesions of variable grade for scoring the presence of each individual characteristic of the architecture and cytology changes that were established by the 2005 WHO classification. The assigned features in each case were correlated with clinical outcomes to understand which features are more commonly associated with malignant transformation. Interestingly, for all individual characteristics, the pairwise inter-examiner and group kappa values ranged from poor to moderate. It appeared that for each characteristic separately there was much dissension. Despite these observations, comparing these data with that from our previous paper on the same slides showed that the inter-observer agreement on the degree of dysplasia either by using the new binary system of "low-risk" or "high-risk" or by using the 2005 WHO classification turned out to be better than the agreement on the individual characteristics of architecture and cytology changes. Certain features show significant association with the clinical outcomes. In the discussion, some explanations to help understanding the sources of variation in grading OED are put forward. In conclusion, grading dysplasia is not an exact science and pathologists are doing their best to reach optimal results. Improvement in the standard of the histopathology reporting of OED lesions could be achieved by consideration of several issues. Of these, there is need for a universal definition of the architectural and cytological features that are the basis of any OED grading process. A minimum dataset for reporting OED lesions should be set up. Also, the use of a consensus scoring process between two or more observers should be encouraged as this would improve inter-observer agreement.

Research paper thumbnail of Oculofaciocardiodental and Lenz microphthalmia syndromes result from distinct classes of mutations in BCOR

Nature Genetics, 2004

Lenz microphthalmia is inherited in an X-linked recessive pattern and comprises microphthalmia, m... more Lenz microphthalmia is inherited in an X-linked recessive pattern and comprises microphthalmia, mental retardation, and skeletal and other anomalies. Two loci associated with this syndrome, MAA (microphthalmia with associated anomalies) and MAA2, are situated respectively at Xq27-q28 (refs. 1,2) and Xp11.4-p21.2 (ref. 3). We identified a substitution, nt 254C→T; P85L, in BCOR (encoding BCL-6interacting corepressor, BCOR 4 ) in affected males from the family with Lenz syndrome previously used to identify the MAA2 locus 3 . Oculofaciocardiodental syndrome (OFCD; OMIM 300166) is inherited in an X-linked dominant pattern with presumed male lethality and comprises microphthalmia, congenital cataracts, radiculomegaly, and cardiac and digital abnormalities. Given their phenotypic overlap, we proposed that OFCD and MAA2-associated Lenz microphthalmia were allelic, and we found different frameshift, deletion and nonsense mutations in BCOR in seven families affected with OFCD. Like wild-type BCOR, BCOR P85L and an OFCDmutant form of BCOR can interact with BCL-6 and efficiently repress transcription. This indicates that these syndromes are likely to result from defects in alternative functions of BCOR, such as interactions with transcriptional partners other than BCL-6. We cloned the zebrafish (Danio rerio) ortholog of BCOR and found that knock-down of this ortholog caused developmental perturbations of the eye, skeleton and central nervous system consistent with the human syndromes, confirming that BCOR is a key transcriptional regulator during early embryogenesis.

Research paper thumbnail of The dental phenotype in familial adenomatous polyposis: diagnostic application of a weighted scoring system for changes on dental panoramic radiographs

Journal of Medical Genetics, 1995

A weighted scoring system (Dental Panoramic Radiograph Score) taking into consideration the natur... more A weighted scoring system (Dental Panoramic Radiograph Score) taking into consideration the nature, extent, and site of osseous and dental changes on dental panoramic radiographs in familial adenomatous polyposis is described. The weighting takes into consideration the incidence of the anomaly in the general population. The reliability of the system was tested by application to 85 people known to be affected by clinical or mutation analysis, 30 people lacking mutation in the adenomatous polyposis gene, and 19 people shown to be at low risk (<1%) by linkage analysis. Using the highest thresholds, a specificity of 100% and sensitivity of -68% was obtained. Ifall positive findings were considered as significant, sensitivity was increased to -82% but the specificity was reduced to -88%. Significant DPRS findings were observed at a significantly higher frequency in patients aged over 20 compared to the patients aged 20 and under. Overall, 68% ofthe affected subjects had significant changes, and -18% had normal appearance on DPR, with the remainder having changes classified as minimal or equivocal. (J Med Genet 1995;32:458-464)

Research paper thumbnail of Complications of the naevoid basal cell carcinoma syndrome: results of a population based study

Journal of Medical Genetics, 1993

There are many potential complications which have been reported in association with the naevoid b... more There are many potential complications which have been reported in association with the naevoid basal cell carcinoma syndrome. We have been able to show the relative frequencies of these problems in a population based study of 84 cases in the north west of England. The major complications of basal cell carcinomas and jaw cysts occur in over 90% of patients by 40 years of age, but may both occur before 10 years of age. Less well described complications are ovarian calcification or fibroma (24%), medulloblastoma (5%), cardiac fibroma (3%), cleft palate (5%), and ophthalmic abnormalities such as squint or cataract (26%). This study more clearly defines the possible complications of the syndrome and gives clearer guidelines for counselling and screening affected and at risk persons.

Research paper thumbnail of A molecular analysis of individuals with neurofibromatosis type 1 (NF1) and optic pathway gliomas (OPGs), and an assessment of genotype-phenotype correlations

Journal of Medical Genetics, 2011

Background.

Research paper thumbnail of Facial infiltrating lipomatosis: A case report and review of literature

International Journal of Surgery Case Reports, 2011

Infiltrating lipomatosis of the face has been described as a congenital disorder in which mature ... more Infiltrating lipomatosis of the face has been described as a congenital disorder in which mature lipocytes invade adjacent tissues in the facial region. The presentation is always unilateral with hypertrophy of hard and soft structures on the affected side of the face. We present a case of a 27-year-old female who reported with a complaint of recurrent unilateral facial swelling with history of two previous resections, the histopathology or details of these surgeries were not available. The patient underwent resection of tumour and the histopathology confirmed it to be infiltrating lipomatosis. The surgery resulted in a definite improvement in the facial asymmetry and the patient is being closely followed up with no evidence of recurrence. The pathogenesis of the condition is unclear, though it has been postulated that the condition is at one end of a spectrum of overgrowth syndromes with classic Proteus syndrome on the other extreme. Management of this condition involves resection of the tumour which in most cases is subtotal to reduce the risk of damage to facial nerve. There is a controversy regarding both timing and extent of resection in the literature and we think the subtotal resection of tumour in an adolescent or older patient can give good aesthetic outcome without compromising facial nerve function. However, the patients should be informed about high rate of recurrence and increase risk of complications with any subsequent surgery.

Research paper thumbnail of Tumor Epression of Major Vault Protein is an Adverse Prognostic Factor for Radiotherapy Outcome in Oropharyngeal Carcinoma

International Journal of Radiation Oncology*Biology*Physics, 2007

Purpose: Vaults are multi-subunit structures that may be involved in nucleo-cytoplasmic transport... more Purpose: Vaults are multi-subunit structures that may be involved in nucleo-cytoplasmic transport, with the major vault protein (MVP or lung resistance-related protein [LRP]) being the main component. The MVP gene is located on chromosome 16 close to the multidrug resistance-associated protein and protein kinase c-␤ genes. The role of MVP in cancer drug resistance has been demonstrated in various cell lines as well as in ovarian carcinomas and acute myeloid leukemia, but nothing is known about its possible role in radiation resistance. Our aim was to examine this in head-and-neck squamous cell carcinoma (HNSCC). Methods and Materials: Archived biopsy material was obtained for 78 patients with squamous cell carcinoma of the oropharynx who received primary radiotherapy with curative intent. Immunohistochemistry was used to detect MVP expression. Locoregional failure and cancer-specific survival were estimated using cumulative incidence and Cox multivariate analyses. Results: In a univariate and multivariate analysis, MVP expression was strongly associated with both locoregional failure and cancer-specific survival. After adjustment for disease site, stage, grade, anemia, smoking, alcohol, gender, and age, the estimated hazard ratio for high MVP (2/3) compared with low (0/1) was 4.98 (95% confidence interval, 2.17-11.42; p ‫؍‬ 0.0002) for locoregional failure and 4.28 (95% confidence interval, 1.85-9.95; p ‫؍‬ 0.001) for cancer-specific mortality. Conclusion: These data are the first to show that MVP may be a useful prognostic marker associated with radiotherapy resistance in a subgroup of patients with HNSCC.

Research paper thumbnail of PD.86 Reproducibility of two grading oral epithelial dysplasia systems: An attempt for predicting the malignant transformation

Oral Oncology Supplement, 2005

Although grading dysplasla is subjective and not highly reproducible, histological grading of ora... more Although grading dysplasla is subjective and not highly reproducible, histological grading of oral epithelial dysplama is still the most widely used method to determine potential malignant transformation. We have proposed a new samphfied binary system to predict malignant transformation using quss~tatatlve measures based on architecture mid cytology criteria. The am1 of tins study was to assess the reproduclNhty of the new grading system and to compare it with the WHO 2003 system. The accuracy of the new system for predicting malignant transformation was also assessed. Materials and Methods: Oral epithelial dysplasla biopsies wath known chmcal outcomes were retrieved from the arctnve of the School of Dentastry, Uinvermty of Manchester (33 cases transformed into squamons carcinoma and 35 were validated as showing no progression). Four pathologists (3 oral pathologists and one general pathologist) reviewed the same H&E slide of each of 68 oral dysplasla lesions using two different grading systems. Interobserver agreement using the Kappa test was measured mid the specaficlty, sensitivity of the binary grading system, mid consequently posative predictive value (PPV) were obtained. Results: The overall Kappa for the WHO grading system was KS 0.33 (95%CI: 0.36 0.54) versusKS 0.63 (95%CI: 0.44-0.91 ) for the new binary system. On the other hand, all pathologists showed satisfactory agreement on the distinctwn of maid dysplasla from severe dysplasla and on carcinoma an situ using WHO 2003 grading system. However, assessment of moderate dysplasaa remains problenhatac. The sensitivity mad specificity of the new binary grading system for predicting mahgnant transfomiatlon an oral epithehal dysplasia were 0.85 mid 0.8 respectively mid the accuracy test valued 82% and PPV was 80%. Conclusion: The new binary grading system complemented with the WHO 2003 grading system and it may have merit in helping clinicians to make the critical clinical decamons particularly for the cases of moderate dysplasla.

Research paper thumbnail of Frequent allelic loss and homozygous deletion in chromosome band 8p23 in oral cancer

International Journal of Cancer, 1999

Frequent loss of heterozygosity on chromosome 8p in a variety of human malignancies, including he... more Frequent loss of heterozygosity on chromosome 8p in a variety of human malignancies, including head and neck cancers, has suggested the presence of a tumor suppressor gene (or genes) associated with the pathogenesis of these cancers. To test the role of genetic alterations at 8p23 in oral carcinogenesis, we studied 51 squamous cell carcinomas of the head and neck and 29 oral squamous cell carcinoma cell lines for allelic loss using 7 microsatellite markers spanning approximately 5 cM of chromosome band 8p23. Twentythree of 51 tumors (45%) and 23 of 29 cell lines (79%) showed allelic loss at 1 or more loci. Three cell lines showed homozygous deletion of loci within a 3 cM region defined by the markers D8S1781 and D8S262. Our results suggest that a tumor suppressor gene (or genes) is located in 8p23 and is associated with the development and/or progression of oral carcinomas. Int.

Research paper thumbnail of Deletion mapping defines three discrete areas of allelic imbalance on chromosome arm 8p in oral and oropharyngeal squamous cell carcinomas

Genes, Chromosomes and Cancer, 1997

Deletions on chromosome arm 8p, as defined by allelic imbalance, are a frequent event in many dif... more Deletions on chromosome arm 8p, as defined by allelic imbalance, are a frequent event in many different types of malignant tumors, including those of the head and neck. These regions are thought to harbor tumor suppressor genes. In order to define a high-density deletion map of this chromosomal arm in oral and oropharyngeal squamous cell carcinomas, we have tested for allelic imbalance in 35 such tumors with 22 short tandem-repeat polymorphisms. Overall, 21 (60%) of the 35 tumors showed allelic imbalance at one or more loci on chromosome arm 8p. Interstitial deletions defined three discrete areas of deletion: at 8p23, 8p22, and 8p12-p21. Tumors of TNM stages II-IV showed a significantly higher frequency of allelic imbalance on 8p than did TNM stage I tumors. Our data suggest that there are least three tumor suppressor loci on chromosome arm 8p that may be implicated in oral carcinogenesis. Furthermore, inactivation of such genes may be associated with high-grade tumors.

Research paper thumbnail of The presence of multiple regions of homozygous deletion at the CSMD1 locus in oral squamous cell carcinoma question the role of CSMD1 in head and neck carcinogenesis

Genes, Chromosomes and Cancer, 2003

We and others previously identified a region of hemizygous or homozygous deletion at chromosome b... more We and others previously identified a region of hemizygous or homozygous deletion at chromosome band 8p23 in oral and oropharyngeal squamous cell carcinomas (OSCCs) and many other cancer types, suggesting the presence of a tumorsuppressor gene (TSG) in this region. Recently, based on a single region of homozygous deletion in head and neck squamous cell carcinomas (HNSCC), a putative TSG, CUB and sushi multiple domains-1 (CSMD1), has been identified. In the present study, we mapped three OSCC cell lines with previously described homozygous deletions at a high resolution onto a detailed physical map. Critically, this map covered a wider region than that used in previous studies, and in contrast to these studies, our results revealed multiple regions of homozygous deletion within a small interval on 8p23. To investigate this deletion pattern further, we generated a panel of 34 sequence tagged site (STS) markers spanning the region and tested these three cell lines and an additional 34 OSCC cell lines, identifying homozygous deletions in a further four. Combining the results from all seven deleted cell lines identified three non-overlapping regions of homozygous deletion. This complex pattern could be consistent with the presence of multiple TSGs or one very large TSG in this region, and/or specific chromosomal instability. CSMD1 spans two of the three deleted regions and, therefore, would appear to be an excellent candidate for a TSG. However, deletion mapping with STSs corresponding to the exons of CSMD1 shows that some of the deletions do not interrupt its coding region, and in other cell lines the coding region is interrupted by two discontinuous homozygous deletions, suggesting the presence of redundant deletions. These results call into question whether the CSMD1 gene is the 8p23 TSG or whether this or any other genes at this locus are involved in the development of OSCC.

Research paper thumbnail of British Society for Oral and Maxillofacial Pathology, UK: minimum curriculum in oral pathology

European Journal of Dental Education, 2004

Research paper thumbnail of Fragile Histidine Triad Expression in Oral Squamous Cell Carcinoma and Precursor Lesions

Clinical Cancer Research, 2006

Fragile histidine triad (FHIT) expression in precursor oral lesions (POL) and oral squamous cell ... more Fragile histidine triad (FHIT) expression in precursor oral lesions (POL) and oral squamous cell carcinomas (OSCC) was studied with regard to (a) the frequency of loss of FHIT expression, (b) whether loss of FHIT expression correlates with degree of dysplasia in POLs, (c) whether FHIT loss predicts high-risk POLs that are more likely to transform, and (d) whether FHIT loss in OSCCs correlates with survival. Ninety-four POLs and 86 OSCCs were immunostained for FHIT. Survival analysis was done for cases with validated clinical outcomes. By optimizing the immunostaining protocol, we found that FHIT is expressed in a distinctive strong nuclear and weak cytoplasmic pattern in oral tissues. Loss of FHIT expression was found in 42 of 94 (45%) POLs and in 66 of 86 (77%) OSCCs. We observed a statistically significant positive correlation between frequency of FHIT loss and increasing grade of dysplasia (chi2=13.8; degrees of freedom=4; P=0.008). Loss of FHIT expression in POLs that progressed to malignancy was more frequent than in those that did not [17 of 25 (68%) versus 12 of 29 (41.4%), respectively]. This difference was statistically significant (chi2=3.8; degrees of freedom=1; P=0.046). In OSCCs, loss of FHIT staining indicated a worse prognosis (survival rate, 36.2%) than when positive FHIT staining was observed (survival rate, 50%), but the difference was not statistically significant (P=0.546, Kaplan-Meier, log-rank). FHIT seems to localize to both nuclear and cytoplasmic domains. FHIT inactivation occurs early in oral carcinogenesis and may be useful molecular marker for progressive dysplastic oral lesions.

Research paper thumbnail of A Sex-Specific Association between a 15q25 Variant and Upper Aerodigestive Tract Cancers

Cancer Epidemiology Biomarkers & Prevention, 2011

Research paper thumbnail of Evaluation of a new binary system of grading oral epithelial dysplasia for prediction of malignant transformation

The aim of this paper is to assess the reproducibility of a novel binary grading system (high/low... more The aim of this paper is to assess the reproducibility of a novel binary grading system (high/low risk) of oral epithelial dysplasia and to compare it with the WHO classification 2005. The accuracy of the new system for predicting malignant transformation was also assessed. Ninety-six consecutive oral epithelial dysplasia biopsies with known clinical outcomes were retrieved from the Oral Pathology archives. A pilot study was conducted on 28 cases to determine the process of classification. Four observers then reviewed the same set of H&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;E stained slides of 68 oral dysplastic lesions using the two grading systems blinded to the clinical outcomes. The overall inter-observer unweighted and weighted kappa agreements for the WHO grading system were Ks = 0.22 (95% CI: 0.11-0.35), Kw = 0.63 (95% CI: 0.42-0.78), respectively, versus K = 0.50 (95% CI: 0.35-0.67) for the new binary system. Interestingly, all pathologists showed satisfactory agreement on the distinction of mild dysplasia from severe dysplasia and from carcinoma in situ using the new WHO classification. However, assessment of moderate dysplasia remains problematic. The sensitivity and specificity of the new binary grading system for predicting malignant transformation in oral epithelial dysplasia were 85% and 80%, respectively and the accuracy was 82%. The new binary grading system complemented the WHO Classification 2005 and may have merit in helping clinicians to make critical clinical decisions particularly for the cases of moderate dysplasia. Histological grading of dysplasia using established criteria is a reproducible prognosticator in oral epithelial dysplasia. Furthermore, the present study showed that more consensus scoring on either the degree of dysplasia, assessment of risk or the presence of each morphological characteristic by a panel should be encouraged.

Research paper thumbnail of Mutation analysis of the cathepsin C gene in Indian families with Papillon-Lefèvre syndrome

Background: PLS is a rare autosomal recessive disorder characterized by early onset periodontopat... more Background: PLS is a rare autosomal recessive disorder characterized by early onset periodontopathia and palmar plantar keratosis. PLS is caused by mutations in the cathepsin C (CTSC) gene. Dipeptidyl-peptidase I encoded by the CTSC gene removes dipeptides from the aminoterminus of protein substrates and mainly plays an immune and inflammatory role. Several mutations have been reported in this gene in patients from several ethnic groups. We report here mutation analysis of the CTSC gene in three Indian families with PLS.

Research paper thumbnail of Tumor Epression of Major Vault Protein is an Adverse Prognostic Factor for Radiotherapy Outcome in Oropharyngeal Carcinoma

Purpose: Vaults are multi-subunit structures that may be involved in nucleo-cytoplasmic transport... more Purpose: Vaults are multi-subunit structures that may be involved in nucleo-cytoplasmic transport, with the major vault protein (MVP or lung resistance-related protein [LRP]) being the main component. The MVP gene is located on chromosome 16 close to the multidrug resistance-associated protein and protein kinase c-␤ genes. The role of MVP in cancer drug resistance has been demonstrated in various cell lines as well as in ovarian carcinomas and acute myeloid leukemia, but nothing is known about its possible role in radiation resistance. Our aim was to examine this in head-and-neck squamous cell carcinoma (HNSCC). Methods and Materials: Archived biopsy material was obtained for 78 patients with squamous cell carcinoma of the oropharynx who received primary radiotherapy with curative intent. Immunohistochemistry was used to detect MVP expression. Locoregional failure and cancer-specific survival were estimated using cumulative incidence and Cox multivariate analyses. Results: In a univariate and multivariate analysis, MVP expression was strongly associated with both locoregional failure and cancer-specific survival. After adjustment for disease site, stage, grade, anemia, smoking, alcohol, gender, and age, the estimated hazard ratio for high MVP (2/3) compared with low (0/1) was 4.98 (95% confidence interval, 2.17-11.42; p ‫؍‬ 0.0002) for locoregional failure and 4.28 (95% confidence interval, 1.85-9.95; p ‫؍‬ 0.001) for cancer-specific mortality. Conclusion: These data are the first to show that MVP may be a useful prognostic marker associated with radiotherapy resistance in a subgroup of patients with HNSCC.

Research paper thumbnail of Mutation analysis of the cathepsin C gene in Indian families with Papillon-Lefèvre syndrome

BMC medical genetics, Jan 12, 2003

PLS is a rare autosomal recessive disorder characterized by early onset periodontopathia and palm... more PLS is a rare autosomal recessive disorder characterized by early onset periodontopathia and palmar plantar keratosis. PLS is caused by mutations in the cathepsin C (CTSC) gene. Dipeptidyl-peptidase I encoded by the CTSC gene removes dipeptides from the amino-terminus of protein substrates and mainly plays an immune and inflammatory role. Several mutations have been reported in this gene in patients from several ethnic groups. We report here mutation analysis of the CTSC gene in three Indian families with PLS. Peripheral blood samples were obtained from individuals belonging to three Indian families with PLS for genomic DNA isolation. Exon-specific intronic primers were used to amplify DNA samples from individuals. PCR products were subsequently sequenced to detect mutations. PCR-SCCP and ASOH analyses were used to determine if mutations were present in normal control individuals. All patients from three families had a classic PLS phenotype, which included palmoplantar keratosis and...

Research paper thumbnail of Using Prior Information from the Medical Literature in GWAS of Oral Cancer Identifies Novel Susceptibility Variant on Chromosome 4 - the AdAPT Method

PloS one, 2012

Genome-wide association studies (GWAS) require large sample sizes to obtain adequate statistical ... more Genome-wide association studies (GWAS) require large sample sizes to obtain adequate statistical power, but it may be possible to increase the power by incorporating complementary data. In this study we investigated the feasibility of automatically retrieving information from the medical literature and leveraging this information in GWAS.

Research paper thumbnail of Evaluation of a new binary system of grading oral epithelial dysplasia for prediction of malignant transformation

Oral Oncology, 2006

The aim of this paper is to assess the reproducibility of a novel binary grading system (high/low... more The aim of this paper is to assess the reproducibility of a novel binary grading system (high/low risk) of oral epithelial dysplasia and to compare it with the WHO classification 2005. The accuracy of the new system for predicting malignant transformation was also assessed. Ninety-six consecutive oral epithelial dysplasia biopsies with known clinical outcomes were retrieved from the Oral Pathology archives. A pilot study was conducted on 28 cases to determine the process of classification. Four observers then reviewed the same set of H&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;E stained slides of 68 oral dysplastic lesions using the two grading systems blinded to the clinical outcomes. The overall inter-observer unweighted and weighted kappa agreements for the WHO grading system were Ks = 0.22 (95% CI: 0.11-0.35), Kw = 0.63 (95% CI: 0.42-0.78), respectively, versus K = 0.50 (95% CI: 0.35-0.67) for the new binary system. Interestingly, all pathologists showed satisfactory agreement on the distinction of mild dysplasia from severe dysplasia and from carcinoma in situ using the new WHO classification. However, assessment of moderate dysplasia remains problematic. The sensitivity and specificity of the new binary grading system for predicting malignant transformation in oral epithelial dysplasia were 85% and 80%, respectively and the accuracy was 82%. The new binary grading system complemented the WHO Classification 2005 and may have merit in helping clinicians to make critical clinical decisions particularly for the cases of moderate dysplasia. Histological grading of dysplasia using established criteria is a reproducible prognosticator in oral epithelial dysplasia. Furthermore, the present study showed that more consensus scoring on either the degree of dysplasia, assessment of risk or the presence of each morphological characteristic by a panel should be encouraged.

Research paper thumbnail of Why oral histopathology suffers inter-observer variability on grading oral epithelial dysplasia: An attempt to understand the sources of variation

Oral Oncology, 2007

The present study attempted to assess the reasons behind the inter-observer variation in grading ... more The present study attempted to assess the reasons behind the inter-observer variation in grading oral epithelial dysplasia (OED). Three oral pathologists and one general pathologist examined 68 histological slides of OED lesions of variable grade for scoring the presence of each individual characteristic of the architecture and cytology changes that were established by the 2005 WHO classification. The assigned features in each case were correlated with clinical outcomes to understand which features are more commonly associated with malignant transformation. Interestingly, for all individual characteristics, the pairwise inter-examiner and group kappa values ranged from poor to moderate. It appeared that for each characteristic separately there was much dissension. Despite these observations, comparing these data with that from our previous paper on the same slides showed that the inter-observer agreement on the degree of dysplasia either by using the new binary system of &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;low-risk&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; or &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;high-risk&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; or by using the 2005 WHO classification turned out to be better than the agreement on the individual characteristics of architecture and cytology changes. Certain features show significant association with the clinical outcomes. In the discussion, some explanations to help understanding the sources of variation in grading OED are put forward. In conclusion, grading dysplasia is not an exact science and pathologists are doing their best to reach optimal results. Improvement in the standard of the histopathology reporting of OED lesions could be achieved by consideration of several issues. Of these, there is need for a universal definition of the architectural and cytological features that are the basis of any OED grading process. A minimum dataset for reporting OED lesions should be set up. Also, the use of a consensus scoring process between two or more observers should be encouraged as this would improve inter-observer agreement.

Research paper thumbnail of Oculofaciocardiodental and Lenz microphthalmia syndromes result from distinct classes of mutations in BCOR

Nature Genetics, 2004

Lenz microphthalmia is inherited in an X-linked recessive pattern and comprises microphthalmia, m... more Lenz microphthalmia is inherited in an X-linked recessive pattern and comprises microphthalmia, mental retardation, and skeletal and other anomalies. Two loci associated with this syndrome, MAA (microphthalmia with associated anomalies) and MAA2, are situated respectively at Xq27-q28 (refs. 1,2) and Xp11.4-p21.2 (ref. 3). We identified a substitution, nt 254C→T; P85L, in BCOR (encoding BCL-6interacting corepressor, BCOR 4 ) in affected males from the family with Lenz syndrome previously used to identify the MAA2 locus 3 . Oculofaciocardiodental syndrome (OFCD; OMIM 300166) is inherited in an X-linked dominant pattern with presumed male lethality and comprises microphthalmia, congenital cataracts, radiculomegaly, and cardiac and digital abnormalities. Given their phenotypic overlap, we proposed that OFCD and MAA2-associated Lenz microphthalmia were allelic, and we found different frameshift, deletion and nonsense mutations in BCOR in seven families affected with OFCD. Like wild-type BCOR, BCOR P85L and an OFCDmutant form of BCOR can interact with BCL-6 and efficiently repress transcription. This indicates that these syndromes are likely to result from defects in alternative functions of BCOR, such as interactions with transcriptional partners other than BCL-6. We cloned the zebrafish (Danio rerio) ortholog of BCOR and found that knock-down of this ortholog caused developmental perturbations of the eye, skeleton and central nervous system consistent with the human syndromes, confirming that BCOR is a key transcriptional regulator during early embryogenesis.

Research paper thumbnail of The dental phenotype in familial adenomatous polyposis: diagnostic application of a weighted scoring system for changes on dental panoramic radiographs

Journal of Medical Genetics, 1995

A weighted scoring system (Dental Panoramic Radiograph Score) taking into consideration the natur... more A weighted scoring system (Dental Panoramic Radiograph Score) taking into consideration the nature, extent, and site of osseous and dental changes on dental panoramic radiographs in familial adenomatous polyposis is described. The weighting takes into consideration the incidence of the anomaly in the general population. The reliability of the system was tested by application to 85 people known to be affected by clinical or mutation analysis, 30 people lacking mutation in the adenomatous polyposis gene, and 19 people shown to be at low risk (<1%) by linkage analysis. Using the highest thresholds, a specificity of 100% and sensitivity of -68% was obtained. Ifall positive findings were considered as significant, sensitivity was increased to -82% but the specificity was reduced to -88%. Significant DPRS findings were observed at a significantly higher frequency in patients aged over 20 compared to the patients aged 20 and under. Overall, 68% ofthe affected subjects had significant changes, and -18% had normal appearance on DPR, with the remainder having changes classified as minimal or equivocal. (J Med Genet 1995;32:458-464)

Research paper thumbnail of Complications of the naevoid basal cell carcinoma syndrome: results of a population based study

Journal of Medical Genetics, 1993

There are many potential complications which have been reported in association with the naevoid b... more There are many potential complications which have been reported in association with the naevoid basal cell carcinoma syndrome. We have been able to show the relative frequencies of these problems in a population based study of 84 cases in the north west of England. The major complications of basal cell carcinomas and jaw cysts occur in over 90% of patients by 40 years of age, but may both occur before 10 years of age. Less well described complications are ovarian calcification or fibroma (24%), medulloblastoma (5%), cardiac fibroma (3%), cleft palate (5%), and ophthalmic abnormalities such as squint or cataract (26%). This study more clearly defines the possible complications of the syndrome and gives clearer guidelines for counselling and screening affected and at risk persons.

Research paper thumbnail of A molecular analysis of individuals with neurofibromatosis type 1 (NF1) and optic pathway gliomas (OPGs), and an assessment of genotype-phenotype correlations

Journal of Medical Genetics, 2011

Background.

Research paper thumbnail of Facial infiltrating lipomatosis: A case report and review of literature

International Journal of Surgery Case Reports, 2011

Infiltrating lipomatosis of the face has been described as a congenital disorder in which mature ... more Infiltrating lipomatosis of the face has been described as a congenital disorder in which mature lipocytes invade adjacent tissues in the facial region. The presentation is always unilateral with hypertrophy of hard and soft structures on the affected side of the face. We present a case of a 27-year-old female who reported with a complaint of recurrent unilateral facial swelling with history of two previous resections, the histopathology or details of these surgeries were not available. The patient underwent resection of tumour and the histopathology confirmed it to be infiltrating lipomatosis. The surgery resulted in a definite improvement in the facial asymmetry and the patient is being closely followed up with no evidence of recurrence. The pathogenesis of the condition is unclear, though it has been postulated that the condition is at one end of a spectrum of overgrowth syndromes with classic Proteus syndrome on the other extreme. Management of this condition involves resection of the tumour which in most cases is subtotal to reduce the risk of damage to facial nerve. There is a controversy regarding both timing and extent of resection in the literature and we think the subtotal resection of tumour in an adolescent or older patient can give good aesthetic outcome without compromising facial nerve function. However, the patients should be informed about high rate of recurrence and increase risk of complications with any subsequent surgery.

Research paper thumbnail of Tumor Epression of Major Vault Protein is an Adverse Prognostic Factor for Radiotherapy Outcome in Oropharyngeal Carcinoma

International Journal of Radiation Oncology*Biology*Physics, 2007

Purpose: Vaults are multi-subunit structures that may be involved in nucleo-cytoplasmic transport... more Purpose: Vaults are multi-subunit structures that may be involved in nucleo-cytoplasmic transport, with the major vault protein (MVP or lung resistance-related protein [LRP]) being the main component. The MVP gene is located on chromosome 16 close to the multidrug resistance-associated protein and protein kinase c-␤ genes. The role of MVP in cancer drug resistance has been demonstrated in various cell lines as well as in ovarian carcinomas and acute myeloid leukemia, but nothing is known about its possible role in radiation resistance. Our aim was to examine this in head-and-neck squamous cell carcinoma (HNSCC). Methods and Materials: Archived biopsy material was obtained for 78 patients with squamous cell carcinoma of the oropharynx who received primary radiotherapy with curative intent. Immunohistochemistry was used to detect MVP expression. Locoregional failure and cancer-specific survival were estimated using cumulative incidence and Cox multivariate analyses. Results: In a univariate and multivariate analysis, MVP expression was strongly associated with both locoregional failure and cancer-specific survival. After adjustment for disease site, stage, grade, anemia, smoking, alcohol, gender, and age, the estimated hazard ratio for high MVP (2/3) compared with low (0/1) was 4.98 (95% confidence interval, 2.17-11.42; p ‫؍‬ 0.0002) for locoregional failure and 4.28 (95% confidence interval, 1.85-9.95; p ‫؍‬ 0.001) for cancer-specific mortality. Conclusion: These data are the first to show that MVP may be a useful prognostic marker associated with radiotherapy resistance in a subgroup of patients with HNSCC.

Research paper thumbnail of PD.86 Reproducibility of two grading oral epithelial dysplasia systems: An attempt for predicting the malignant transformation

Oral Oncology Supplement, 2005

Although grading dysplasla is subjective and not highly reproducible, histological grading of ora... more Although grading dysplasla is subjective and not highly reproducible, histological grading of oral epithelial dysplama is still the most widely used method to determine potential malignant transformation. We have proposed a new samphfied binary system to predict malignant transformation using quss~tatatlve measures based on architecture mid cytology criteria. The am1 of tins study was to assess the reproduclNhty of the new grading system and to compare it with the WHO 2003 system. The accuracy of the new system for predicting malignant transformation was also assessed. Materials and Methods: Oral epithelial dysplasla biopsies wath known chmcal outcomes were retrieved from the arctnve of the School of Dentastry, Uinvermty of Manchester (33 cases transformed into squamons carcinoma and 35 were validated as showing no progression). Four pathologists (3 oral pathologists and one general pathologist) reviewed the same H&E slide of each of 68 oral dysplasla lesions using two different grading systems. Interobserver agreement using the Kappa test was measured mid the specaficlty, sensitivity of the binary grading system, mid consequently posative predictive value (PPV) were obtained. Results: The overall Kappa for the WHO grading system was KS 0.33 (95%CI: 0.36 0.54) versusKS 0.63 (95%CI: 0.44-0.91 ) for the new binary system. On the other hand, all pathologists showed satisfactory agreement on the distinctwn of maid dysplasla from severe dysplasla and on carcinoma an situ using WHO 2003 grading system. However, assessment of moderate dysplasaa remains problenhatac. The sensitivity mad specificity of the new binary grading system for predicting mahgnant transfomiatlon an oral epithehal dysplasia were 0.85 mid 0.8 respectively mid the accuracy test valued 82% and PPV was 80%. Conclusion: The new binary grading system complemented with the WHO 2003 grading system and it may have merit in helping clinicians to make the critical clinical decamons particularly for the cases of moderate dysplasla.

Research paper thumbnail of Frequent allelic loss and homozygous deletion in chromosome band 8p23 in oral cancer

International Journal of Cancer, 1999

Frequent loss of heterozygosity on chromosome 8p in a variety of human malignancies, including he... more Frequent loss of heterozygosity on chromosome 8p in a variety of human malignancies, including head and neck cancers, has suggested the presence of a tumor suppressor gene (or genes) associated with the pathogenesis of these cancers. To test the role of genetic alterations at 8p23 in oral carcinogenesis, we studied 51 squamous cell carcinomas of the head and neck and 29 oral squamous cell carcinoma cell lines for allelic loss using 7 microsatellite markers spanning approximately 5 cM of chromosome band 8p23. Twentythree of 51 tumors (45%) and 23 of 29 cell lines (79%) showed allelic loss at 1 or more loci. Three cell lines showed homozygous deletion of loci within a 3 cM region defined by the markers D8S1781 and D8S262. Our results suggest that a tumor suppressor gene (or genes) is located in 8p23 and is associated with the development and/or progression of oral carcinomas. Int.

Research paper thumbnail of Deletion mapping defines three discrete areas of allelic imbalance on chromosome arm 8p in oral and oropharyngeal squamous cell carcinomas

Genes, Chromosomes and Cancer, 1997

Deletions on chromosome arm 8p, as defined by allelic imbalance, are a frequent event in many dif... more Deletions on chromosome arm 8p, as defined by allelic imbalance, are a frequent event in many different types of malignant tumors, including those of the head and neck. These regions are thought to harbor tumor suppressor genes. In order to define a high-density deletion map of this chromosomal arm in oral and oropharyngeal squamous cell carcinomas, we have tested for allelic imbalance in 35 such tumors with 22 short tandem-repeat polymorphisms. Overall, 21 (60%) of the 35 tumors showed allelic imbalance at one or more loci on chromosome arm 8p. Interstitial deletions defined three discrete areas of deletion: at 8p23, 8p22, and 8p12-p21. Tumors of TNM stages II-IV showed a significantly higher frequency of allelic imbalance on 8p than did TNM stage I tumors. Our data suggest that there are least three tumor suppressor loci on chromosome arm 8p that may be implicated in oral carcinogenesis. Furthermore, inactivation of such genes may be associated with high-grade tumors.

Research paper thumbnail of The presence of multiple regions of homozygous deletion at the CSMD1 locus in oral squamous cell carcinoma question the role of CSMD1 in head and neck carcinogenesis

Genes, Chromosomes and Cancer, 2003

We and others previously identified a region of hemizygous or homozygous deletion at chromosome b... more We and others previously identified a region of hemizygous or homozygous deletion at chromosome band 8p23 in oral and oropharyngeal squamous cell carcinomas (OSCCs) and many other cancer types, suggesting the presence of a tumorsuppressor gene (TSG) in this region. Recently, based on a single region of homozygous deletion in head and neck squamous cell carcinomas (HNSCC), a putative TSG, CUB and sushi multiple domains-1 (CSMD1), has been identified. In the present study, we mapped three OSCC cell lines with previously described homozygous deletions at a high resolution onto a detailed physical map. Critically, this map covered a wider region than that used in previous studies, and in contrast to these studies, our results revealed multiple regions of homozygous deletion within a small interval on 8p23. To investigate this deletion pattern further, we generated a panel of 34 sequence tagged site (STS) markers spanning the region and tested these three cell lines and an additional 34 OSCC cell lines, identifying homozygous deletions in a further four. Combining the results from all seven deleted cell lines identified three non-overlapping regions of homozygous deletion. This complex pattern could be consistent with the presence of multiple TSGs or one very large TSG in this region, and/or specific chromosomal instability. CSMD1 spans two of the three deleted regions and, therefore, would appear to be an excellent candidate for a TSG. However, deletion mapping with STSs corresponding to the exons of CSMD1 shows that some of the deletions do not interrupt its coding region, and in other cell lines the coding region is interrupted by two discontinuous homozygous deletions, suggesting the presence of redundant deletions. These results call into question whether the CSMD1 gene is the 8p23 TSG or whether this or any other genes at this locus are involved in the development of OSCC.

Research paper thumbnail of British Society for Oral and Maxillofacial Pathology, UK: minimum curriculum in oral pathology

European Journal of Dental Education, 2004

Research paper thumbnail of Fragile Histidine Triad Expression in Oral Squamous Cell Carcinoma and Precursor Lesions

Clinical Cancer Research, 2006

Fragile histidine triad (FHIT) expression in precursor oral lesions (POL) and oral squamous cell ... more Fragile histidine triad (FHIT) expression in precursor oral lesions (POL) and oral squamous cell carcinomas (OSCC) was studied with regard to (a) the frequency of loss of FHIT expression, (b) whether loss of FHIT expression correlates with degree of dysplasia in POLs, (c) whether FHIT loss predicts high-risk POLs that are more likely to transform, and (d) whether FHIT loss in OSCCs correlates with survival. Ninety-four POLs and 86 OSCCs were immunostained for FHIT. Survival analysis was done for cases with validated clinical outcomes. By optimizing the immunostaining protocol, we found that FHIT is expressed in a distinctive strong nuclear and weak cytoplasmic pattern in oral tissues. Loss of FHIT expression was found in 42 of 94 (45%) POLs and in 66 of 86 (77%) OSCCs. We observed a statistically significant positive correlation between frequency of FHIT loss and increasing grade of dysplasia (chi2=13.8; degrees of freedom=4; P=0.008). Loss of FHIT expression in POLs that progressed to malignancy was more frequent than in those that did not [17 of 25 (68%) versus 12 of 29 (41.4%), respectively]. This difference was statistically significant (chi2=3.8; degrees of freedom=1; P=0.046). In OSCCs, loss of FHIT staining indicated a worse prognosis (survival rate, 36.2%) than when positive FHIT staining was observed (survival rate, 50%), but the difference was not statistically significant (P=0.546, Kaplan-Meier, log-rank). FHIT seems to localize to both nuclear and cytoplasmic domains. FHIT inactivation occurs early in oral carcinogenesis and may be useful molecular marker for progressive dysplastic oral lesions.

Research paper thumbnail of A Sex-Specific Association between a 15q25 Variant and Upper Aerodigestive Tract Cancers

Cancer Epidemiology Biomarkers & Prevention, 2011