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International Journal of Research in Medical Sciences
Background: Potassium is one of the most commonly affected analytes in a hemolysed sample. Many f... more Background: Potassium is one of the most commonly affected analytes in a hemolysed sample. Many formulae have been devised to predict the actual potassium in a hemolysed sample. This study was performed to compare the predicted potassium value in a hemolysed sample to that of potassium value in a non-hemolysed sample of the same patient.Methods: The hemolytic index (HI) derived equation from the paper by Dimeski et al was used to calculate potassium value in this study. A total of 99 paired samples were evaluated where the first sample in a pair was the hemolysed one and the other sample was a non-hemolysed one.Results: This study found that the potassium value in a sample and its respective HI have weak positive correlation. However, there was a statistically significant strong positive correlation between the estimated potassium of hemolysed sample to that of the potassium in the non-hemolysed sample.Conclusions: Hence, we conclude that it is feasible to use HI-derived equation to...
International Journal of Research in Medical Sciences
Background:It is an established fact that dyslipidemia is one of the major risk factors for cardi... more Background:It is an established fact that dyslipidemia is one of the major risk factors for cardiovascular diseases like myocardial infarction. Major well-known alterations in lipid profile include high serum cholesterol, low density lipoprotein cholesterol (LDL-C), triglyceride and low high density lipoprotein cholesterol (HDL-C). Recently, it has been found that atherogenic index of plasma (AIP); which is a logarithmically transformed ratio of triglyceride and HDL-C; can predict cardio-vascular disease risk and can also be used for cardio-vascular disease risk stratification. In this study we have calculated the AIP from fasting lipid profile of patients suffering from myocardial infarction and tried to assess the correlation between AIP and myocardial infarction.Methods: The study comprised of fifty patients suffering from myocardial infarction aged more than 18 with no prior history of cardiovascular diseases. We measured fasting lipid profile using Vitros 5600 full auto analyze...
International Journal of Advanced Research, Aug 31, 2017
Tumour biology : the journal of the International Society for Oncodevelopmental Biology and Medicine, Jan 6, 2016
We investigated the role of BRCA1, MDM2, and p53 in the pathogenesis of head and neck cancer (HNC... more We investigated the role of BRCA1, MDM2, and p53 in the pathogenesis of head and neck cancer (HNC) and evaluated their potential utility as blood-based predictive biomarkers of HNC. Immunostaining of tissue biopsies and whole blood lymphocytes (WBL) of 36 HNC patients were evaluated by immunohistochemistry (IHC) and immunocytochemistry (ICC), respectively. The staining intensities of BRCA1 and MDM2 in matched tissue and blood samples were significantly associated with cancer stage. Furthermore, the cellular levels of BRCA1, MDM2, and p53 were evaluated in peripheral blood lymphocytes (PBL) of 134 HNC patients and 126 controls by slot blotting. Expression levels of all three proteins in PBL of HNC patients varied significantly with respect to those of controls (p < 0.0001) with BRCA1 downregulated to 75 % of control and MDM2 and p53 upregulated to 1.7- and 1.4-fold the control level, respectively. Moreover, positive correlation was observed between expression levels of BRCA1, MDM2...
Genetic polymorphisms in tobacco-metabolizing genes may modulate the risk of head and neck cancer... more Genetic polymorphisms in tobacco-metabolizing genes may modulate the risk of head and neck cancer (HNC). In Northeast India, head and neck cancers and tobacco consumption remains most prevalent. The aim of the study was to investigate the combined effect of cytochrome P450 1A1 (CYP1A1) T3801C, glutathione S-transferases (GSTs) genes polymorphisms and smoking and tobacco-betel quid chewing in the risk of HNC. The study included 420 subjects (180 cases and 240 controls) from Northeast Indian population. Polymorphisms of CYP1A1 T3801C and GST (M1 & T1) were studied by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) and multiplex PCR, respectively. Logistic regression (LR) and multifactor dimensionality reduction (MDR) approach were applied for statistical analysis. LR analysis revealed that subjects carrying CYP1A1 TC/CC + GSTM1 null genotypes had 3.52-fold (P < 0.001) increase the risk of head and neck squamous cell carcinoma (HNSCC). Smokers carrying CYP1A1 TC/CC + GSTM1 null and CYP1A1 TC/CC + GSTT1 null genotypes showed significant association with HNC risk (odds ratio [OR] = 6.42; P < 0.001 and 3.86; P = 0.005, respectively). Similarly, tobacco-betel quid chewers carrying CYP1A1 TC/CC + GSTM1 null genotypes also had several fold increased risk of HNC (P < 0.001). In MDR analysis, the best model for HNSCC risk was the four-factor model of tobacco-betel quid chewing, smoking, CYP1A1 TC/CC, and GSTM1 null genotypes (testing balance accuracy [TBA] = 0.6292; cross-validation consistency [CVC] = 9/10 and P < 0.0001). These findings suggest that interaction of combined genotypes of carcinogen-metabolizing genes with environmental factors might modulate susceptibility of HNC in Northeast Indian population.
Tobacco consumption in various forms is one of the major risk factor for the development of head ... more Tobacco consumption in various forms is one of the major risk factor for the development of head and neck squamous cell carcinoma. Polymorphisms in XRCC1 and XRCC2 genes may alter an individual’s susceptibility to tobacco-related cancers. Here, we have investigated the interaction of XRCC1 (Arg399Gln) and XRCC2 (Arg188His) polymorphism and tobacco exposure in the progression of HNSCC in northeast Indian population. The population-based case–control study includes 110 HNSCC patients and 140 controls. The polymorphisms of XRCC1 and XRCC2 were studied by means of PCR–RFLP, and the results were confirmed by DNA sequencing. Smokers and tobacco-betel quid chewers were significantly higher in cases (P = 0.045 and 0.033). The variant homozygote AA genotype of XRCC1 Arg399Gln and heterozygote GA genotype of XRCC2 Arg188His has an increased risk toward HNSCC (OR 2.43; P = 0.031 and OR 3.29; P < 0.01, respectively). The interaction between tobacco-betel quid chewing and variant genotypes of XRCC1 and XRCC2 resulted in several fold increase the risk of HNSCC, when compared to non-chewers. Heavy smokers carrying XRCC1 AA and XRCC2 GA genotypes had a significantly higher risk of HNSCC compared to never smokers (P = 0.017 and 0.003, respectively). Upon gene–gene interaction analysis, individuals carrying both XRCC1 GA (Arg/Gln) and XRCC2 GA (Arg/His) genotypes had the highest risk of HNSCC (P = 0.001).Our finding suggests that interaction of tobacco and polymorphisms of XRCC1 and XRCC2 increases the risk of HNSCC. Furthermore, cross talk between these two DNA repair genes might modulate susceptibility toward HNSCC.
Molecular Carcinogenesis, 2014
Human papillomavirus (HPV) has been recently associated with squamous cell carcinoma of upper aer... more Human papillomavirus (HPV) has been recently associated with squamous cell carcinoma of upper aerodigestive tract (SCC of UADT), but its possible role in promoting aberrant methylation in these tumors has largely remained unexplored. Herein, we investigated the association of HPV with aberrant methylation in tumor-related genes/loci consisting of the classical CpG Island Methylator Phenotype (CIMP) panel markers (p16, MLH1, MINT1, MINT2, and MINT31) and other frequently methylated cancer-related genes (DAPK1, GSTP1, BRCA1, ECAD, and RASSF1) and survival of UDAT cancers. The study includes 219 SCC of UADT patients from different hospitals of Northeast India. Detection of HPV and aberrant promoter methylation was performed by PCR and Methylation Specific PCR respectively. Association study was conducted by Logistic regression analysis and overall survival analysis was done by Kaplan-Meier plot. HPV was detected in 37% of cases, with HPV-18 as the major high-risk sub-type. Although HPV presence did not seem to affect survival in overall UADT cancers, but was associated with a favourable prognosis in head and neck squamous cell carcinoma. Hierarchical clustering revealed three distinct clusters with different methylation profile and HPV presence. Among these, the CIMP-high subgroup exhibited the highest HPV positive cases (66%). Furthermore, multivariate analysis revealed a strong synergistic association of HPV and tobacco towards modulating promoter hypermethylation in UADT cancer (OR ¼ 27.50 [95% CI ¼ 11.51-88.03] for CIMP-high vs. CIMP-low). The present study proposes a potential role of HPV in impelling aberrant methylation in specific tumor related loci, which might contribute in the initiation and progression of SCC of UADT.
Tumor Biology, 2014
Head and neck squamous cell carcinoma (HNSCC) diagnosis involves histopathological investigations... more Head and neck squamous cell carcinoma (HNSCC) diagnosis involves histopathological investigations with intervention procedures. Widely accepted biochemical panels for HNSCC detection is not available yet. We tried to find out the effectiveness of the serum-based biochemical markers for their prognostic significance in HNSCC. We collected fresh blood samples of 80 HNSCC patients and 100 healthy subjects. Samples were analyzed for absolute levels of arginase (ARG), ornithine aminotransferase (OAT), catalase (CAT), lactate dehydrogenase (LDH), amylase (AMY) activity, and C-reactive protein (CRP). Receiver-operator characteristic curves and Fagan&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s nomograms were generated. Out of six parameters studied, four (OAT, CAT, LDH, and AMY) did not show biologically significant differences to be used as biomarkers. Significant elevation in serum ARG and CRP levels were observed in HNSCC. The individual estimation of ARG and CRP showed lower specificity, but their combination improved the specificity level to 95%. Our results suggest that serum ARG and CRP together can efficiently diagnose HNSCC.
Background: Polymorphisms in the MDM2 309 (T>G) and TP53 72 (G>C) genes are reported to increase ... more Background: Polymorphisms in the MDM2 309 (T>G) and TP53 72 (G>C) genes are reported to increase the susceptibility to head and neck cancer (HNC) in various populations. The risk for HNC is also strongly associated with etiologic habits such as smoking, alcohol consumption and/or chewing of betel quid (BQ). In a case-control study, we investigated the significance of the above polymorphisms alone, and upon interaction with
one another as well as with various etiologic habits in determining HNC risk in a Northeast Indian population.
Materials and Methods: Genotyping at 309 MDM2 and 72 TP53 in 122 HNC patients and 86 cancer free healthy
controls was performed by PCR using allele specific primers, and the results were confirmed by DNA sequencing.
Results: Individuals with the GG mutant allele of MDM2 showed a higher risk for HNC in comparison to those with the TT wild type allele (OR=1.9, 95%CI: 1.1-3.3) (p=0.022). The risk was further increased in females by ~4-fold (OR=4.6, 95% CI: 1.1-19.4) (P=0.04). TP53 polymorphism did not contribute to HNC risk alone; however, interaction between the TP53 GC and MDM2 GG genotypes resulted in significant risk (OR=4.9, 95%
CI: 0.2-105.1) (p=0.04). Smokers, BQ- chewers and alcohol consumers showed statistically significant and dosedependent
increase in HNC risk, irrespective of the MDM2 genotype. Conclusions: MDM2 genotype could serve as an important predictive biomarker for HNC risk in the population of Northeast India.
In the present study, we investigated the effect of the DNA repair gene polymorphisms XPD Asp312... more In the present study, we investigated the effect of
the DNA repair gene polymorphisms XPD Asp312Asn
(G>A), APE1 Asp148Glu (T>G), and MUTYH Tyr165Cys
(G>A) on the risk for head and neck cancer (HNC) in association
with tobacco use in a population of Northeast India. The
study subjects comprised of 80 HNC patients and 92 healthy
controls. Genotyping was performed using amplification refractory
mutation system—PCR (ARMS-PCR) for XPD
Asp312Asn (G>A) and PCR using confronting two-pair
primers (PCR-CTPP) for APE1 Asp148Glu (T>G) and
MUTYH Tyr165Cys (G>A). The XPD Asp/Asn genotype increased
the risk for HNC by 2-fold (odds ratio, OR=2.072;
95 % CI, 1.025–4.190; p<0.05). Interaction between APE1
Asp/Asp and XPD Asp/Asn as well as MUTYH Tyr/Tyr and
XPD Asp/Asn genotypes further increased the risk by 2.9
(OR=2.97; 95 % CI, 1.16–7.61; p<0.05) and 2.3 (OR=
2.37; 95 % CI, 1.11–5.10; p<0.05) folds, respectively. The
risk was further increased in heavy smokers with the XPD
Asp/Asn genotype and heavy tobacco chewers with XPD
Asn/Asn genotype by 7.7-fold (OR=7.749; 95 % CI, 2.53–
23.70; p<0.05) and 10-fold (OR=10; 95 % CI, 1.26–79.13;p<0.05), respectively. We thus conclude that the XPD
Asp312Asn and APE1 Asp148Glu polymorphisms increase
the risk for HNC in association with smoking and/or tobacco
chewing in the population under study.
International Journal of Research in Medical Sciences
Background: Potassium is one of the most commonly affected analytes in a hemolysed sample. Many f... more Background: Potassium is one of the most commonly affected analytes in a hemolysed sample. Many formulae have been devised to predict the actual potassium in a hemolysed sample. This study was performed to compare the predicted potassium value in a hemolysed sample to that of potassium value in a non-hemolysed sample of the same patient.Methods: The hemolytic index (HI) derived equation from the paper by Dimeski et al was used to calculate potassium value in this study. A total of 99 paired samples were evaluated where the first sample in a pair was the hemolysed one and the other sample was a non-hemolysed one.Results: This study found that the potassium value in a sample and its respective HI have weak positive correlation. However, there was a statistically significant strong positive correlation between the estimated potassium of hemolysed sample to that of the potassium in the non-hemolysed sample.Conclusions: Hence, we conclude that it is feasible to use HI-derived equation to...
International Journal of Research in Medical Sciences
Background:It is an established fact that dyslipidemia is one of the major risk factors for cardi... more Background:It is an established fact that dyslipidemia is one of the major risk factors for cardiovascular diseases like myocardial infarction. Major well-known alterations in lipid profile include high serum cholesterol, low density lipoprotein cholesterol (LDL-C), triglyceride and low high density lipoprotein cholesterol (HDL-C). Recently, it has been found that atherogenic index of plasma (AIP); which is a logarithmically transformed ratio of triglyceride and HDL-C; can predict cardio-vascular disease risk and can also be used for cardio-vascular disease risk stratification. In this study we have calculated the AIP from fasting lipid profile of patients suffering from myocardial infarction and tried to assess the correlation between AIP and myocardial infarction.Methods: The study comprised of fifty patients suffering from myocardial infarction aged more than 18 with no prior history of cardiovascular diseases. We measured fasting lipid profile using Vitros 5600 full auto analyze...
International Journal of Advanced Research, Aug 31, 2017
Tumour biology : the journal of the International Society for Oncodevelopmental Biology and Medicine, Jan 6, 2016
We investigated the role of BRCA1, MDM2, and p53 in the pathogenesis of head and neck cancer (HNC... more We investigated the role of BRCA1, MDM2, and p53 in the pathogenesis of head and neck cancer (HNC) and evaluated their potential utility as blood-based predictive biomarkers of HNC. Immunostaining of tissue biopsies and whole blood lymphocytes (WBL) of 36 HNC patients were evaluated by immunohistochemistry (IHC) and immunocytochemistry (ICC), respectively. The staining intensities of BRCA1 and MDM2 in matched tissue and blood samples were significantly associated with cancer stage. Furthermore, the cellular levels of BRCA1, MDM2, and p53 were evaluated in peripheral blood lymphocytes (PBL) of 134 HNC patients and 126 controls by slot blotting. Expression levels of all three proteins in PBL of HNC patients varied significantly with respect to those of controls (p < 0.0001) with BRCA1 downregulated to 75 % of control and MDM2 and p53 upregulated to 1.7- and 1.4-fold the control level, respectively. Moreover, positive correlation was observed between expression levels of BRCA1, MDM2...
Genetic polymorphisms in tobacco-metabolizing genes may modulate the risk of head and neck cancer... more Genetic polymorphisms in tobacco-metabolizing genes may modulate the risk of head and neck cancer (HNC). In Northeast India, head and neck cancers and tobacco consumption remains most prevalent. The aim of the study was to investigate the combined effect of cytochrome P450 1A1 (CYP1A1) T3801C, glutathione S-transferases (GSTs) genes polymorphisms and smoking and tobacco-betel quid chewing in the risk of HNC. The study included 420 subjects (180 cases and 240 controls) from Northeast Indian population. Polymorphisms of CYP1A1 T3801C and GST (M1 & T1) were studied by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) and multiplex PCR, respectively. Logistic regression (LR) and multifactor dimensionality reduction (MDR) approach were applied for statistical analysis. LR analysis revealed that subjects carrying CYP1A1 TC/CC + GSTM1 null genotypes had 3.52-fold (P < 0.001) increase the risk of head and neck squamous cell carcinoma (HNSCC). Smokers carrying CYP1A1 TC/CC + GSTM1 null and CYP1A1 TC/CC + GSTT1 null genotypes showed significant association with HNC risk (odds ratio [OR] = 6.42; P < 0.001 and 3.86; P = 0.005, respectively). Similarly, tobacco-betel quid chewers carrying CYP1A1 TC/CC + GSTM1 null genotypes also had several fold increased risk of HNC (P < 0.001). In MDR analysis, the best model for HNSCC risk was the four-factor model of tobacco-betel quid chewing, smoking, CYP1A1 TC/CC, and GSTM1 null genotypes (testing balance accuracy [TBA] = 0.6292; cross-validation consistency [CVC] = 9/10 and P < 0.0001). These findings suggest that interaction of combined genotypes of carcinogen-metabolizing genes with environmental factors might modulate susceptibility of HNC in Northeast Indian population.
Tobacco consumption in various forms is one of the major risk factor for the development of head ... more Tobacco consumption in various forms is one of the major risk factor for the development of head and neck squamous cell carcinoma. Polymorphisms in XRCC1 and XRCC2 genes may alter an individual’s susceptibility to tobacco-related cancers. Here, we have investigated the interaction of XRCC1 (Arg399Gln) and XRCC2 (Arg188His) polymorphism and tobacco exposure in the progression of HNSCC in northeast Indian population. The population-based case–control study includes 110 HNSCC patients and 140 controls. The polymorphisms of XRCC1 and XRCC2 were studied by means of PCR–RFLP, and the results were confirmed by DNA sequencing. Smokers and tobacco-betel quid chewers were significantly higher in cases (P = 0.045 and 0.033). The variant homozygote AA genotype of XRCC1 Arg399Gln and heterozygote GA genotype of XRCC2 Arg188His has an increased risk toward HNSCC (OR 2.43; P = 0.031 and OR 3.29; P < 0.01, respectively). The interaction between tobacco-betel quid chewing and variant genotypes of XRCC1 and XRCC2 resulted in several fold increase the risk of HNSCC, when compared to non-chewers. Heavy smokers carrying XRCC1 AA and XRCC2 GA genotypes had a significantly higher risk of HNSCC compared to never smokers (P = 0.017 and 0.003, respectively). Upon gene–gene interaction analysis, individuals carrying both XRCC1 GA (Arg/Gln) and XRCC2 GA (Arg/His) genotypes had the highest risk of HNSCC (P = 0.001).Our finding suggests that interaction of tobacco and polymorphisms of XRCC1 and XRCC2 increases the risk of HNSCC. Furthermore, cross talk between these two DNA repair genes might modulate susceptibility toward HNSCC.
Molecular Carcinogenesis, 2014
Human papillomavirus (HPV) has been recently associated with squamous cell carcinoma of upper aer... more Human papillomavirus (HPV) has been recently associated with squamous cell carcinoma of upper aerodigestive tract (SCC of UADT), but its possible role in promoting aberrant methylation in these tumors has largely remained unexplored. Herein, we investigated the association of HPV with aberrant methylation in tumor-related genes/loci consisting of the classical CpG Island Methylator Phenotype (CIMP) panel markers (p16, MLH1, MINT1, MINT2, and MINT31) and other frequently methylated cancer-related genes (DAPK1, GSTP1, BRCA1, ECAD, and RASSF1) and survival of UDAT cancers. The study includes 219 SCC of UADT patients from different hospitals of Northeast India. Detection of HPV and aberrant promoter methylation was performed by PCR and Methylation Specific PCR respectively. Association study was conducted by Logistic regression analysis and overall survival analysis was done by Kaplan-Meier plot. HPV was detected in 37% of cases, with HPV-18 as the major high-risk sub-type. Although HPV presence did not seem to affect survival in overall UADT cancers, but was associated with a favourable prognosis in head and neck squamous cell carcinoma. Hierarchical clustering revealed three distinct clusters with different methylation profile and HPV presence. Among these, the CIMP-high subgroup exhibited the highest HPV positive cases (66%). Furthermore, multivariate analysis revealed a strong synergistic association of HPV and tobacco towards modulating promoter hypermethylation in UADT cancer (OR ¼ 27.50 [95% CI ¼ 11.51-88.03] for CIMP-high vs. CIMP-low). The present study proposes a potential role of HPV in impelling aberrant methylation in specific tumor related loci, which might contribute in the initiation and progression of SCC of UADT.
Tumor Biology, 2014
Head and neck squamous cell carcinoma (HNSCC) diagnosis involves histopathological investigations... more Head and neck squamous cell carcinoma (HNSCC) diagnosis involves histopathological investigations with intervention procedures. Widely accepted biochemical panels for HNSCC detection is not available yet. We tried to find out the effectiveness of the serum-based biochemical markers for their prognostic significance in HNSCC. We collected fresh blood samples of 80 HNSCC patients and 100 healthy subjects. Samples were analyzed for absolute levels of arginase (ARG), ornithine aminotransferase (OAT), catalase (CAT), lactate dehydrogenase (LDH), amylase (AMY) activity, and C-reactive protein (CRP). Receiver-operator characteristic curves and Fagan&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s nomograms were generated. Out of six parameters studied, four (OAT, CAT, LDH, and AMY) did not show biologically significant differences to be used as biomarkers. Significant elevation in serum ARG and CRP levels were observed in HNSCC. The individual estimation of ARG and CRP showed lower specificity, but their combination improved the specificity level to 95%. Our results suggest that serum ARG and CRP together can efficiently diagnose HNSCC.
Background: Polymorphisms in the MDM2 309 (T>G) and TP53 72 (G>C) genes are reported to increase ... more Background: Polymorphisms in the MDM2 309 (T>G) and TP53 72 (G>C) genes are reported to increase the susceptibility to head and neck cancer (HNC) in various populations. The risk for HNC is also strongly associated with etiologic habits such as smoking, alcohol consumption and/or chewing of betel quid (BQ). In a case-control study, we investigated the significance of the above polymorphisms alone, and upon interaction with
one another as well as with various etiologic habits in determining HNC risk in a Northeast Indian population.
Materials and Methods: Genotyping at 309 MDM2 and 72 TP53 in 122 HNC patients and 86 cancer free healthy
controls was performed by PCR using allele specific primers, and the results were confirmed by DNA sequencing.
Results: Individuals with the GG mutant allele of MDM2 showed a higher risk for HNC in comparison to those with the TT wild type allele (OR=1.9, 95%CI: 1.1-3.3) (p=0.022). The risk was further increased in females by ~4-fold (OR=4.6, 95% CI: 1.1-19.4) (P=0.04). TP53 polymorphism did not contribute to HNC risk alone; however, interaction between the TP53 GC and MDM2 GG genotypes resulted in significant risk (OR=4.9, 95%
CI: 0.2-105.1) (p=0.04). Smokers, BQ- chewers and alcohol consumers showed statistically significant and dosedependent
increase in HNC risk, irrespective of the MDM2 genotype. Conclusions: MDM2 genotype could serve as an important predictive biomarker for HNC risk in the population of Northeast India.
In the present study, we investigated the effect of the DNA repair gene polymorphisms XPD Asp312... more In the present study, we investigated the effect of
the DNA repair gene polymorphisms XPD Asp312Asn
(G>A), APE1 Asp148Glu (T>G), and MUTYH Tyr165Cys
(G>A) on the risk for head and neck cancer (HNC) in association
with tobacco use in a population of Northeast India. The
study subjects comprised of 80 HNC patients and 92 healthy
controls. Genotyping was performed using amplification refractory
mutation system—PCR (ARMS-PCR) for XPD
Asp312Asn (G>A) and PCR using confronting two-pair
primers (PCR-CTPP) for APE1 Asp148Glu (T>G) and
MUTYH Tyr165Cys (G>A). The XPD Asp/Asn genotype increased
the risk for HNC by 2-fold (odds ratio, OR=2.072;
95 % CI, 1.025–4.190; p<0.05). Interaction between APE1
Asp/Asp and XPD Asp/Asn as well as MUTYH Tyr/Tyr and
XPD Asp/Asn genotypes further increased the risk by 2.9
(OR=2.97; 95 % CI, 1.16–7.61; p<0.05) and 2.3 (OR=
2.37; 95 % CI, 1.11–5.10; p<0.05) folds, respectively. The
risk was further increased in heavy smokers with the XPD
Asp/Asn genotype and heavy tobacco chewers with XPD
Asn/Asn genotype by 7.7-fold (OR=7.749; 95 % CI, 2.53–
23.70; p<0.05) and 10-fold (OR=10; 95 % CI, 1.26–79.13;p<0.05), respectively. We thus conclude that the XPD
Asp312Asn and APE1 Asp148Glu polymorphisms increase
the risk for HNC in association with smoking and/or tobacco
chewing in the population under study.