Loss of heterozygosity of p53 in oral cancers demonstrated by the polymerase chain reaction (original) (raw)
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Loss of heterozygosity in p53 gene found in oral squamous cell carcinoma patients of Pakistan
Pakistan Journal of Biochemistry and Molecular Biology, 2011
Abstract: Oral squamous cell carcinoma (OSCC) is the leading cause of death in the developing countries like Pakistan. The major risk factor for developing OSCC is the excessive chewing habit of paan (betel quid) chaliya (betel nut), tobacco, niswar (type of dipping tobacco, made from fresh tobacco leaves, calcium oxide, and wood ash) gutka (a preparation of crushed betel nut, tobacco and sweet or savory flavors) and manpuri (the powder of betel nut, tobacco and slaked lime). The p53 gene is the extensively studied tumor suppressor gene involved in the suppression of tumor. The germ line mutation/polymorphism of p53 gene has been reported to be involved in multiple steps of carcinogenesis. It has been reported that exon 4-9 were the hot spots of the mutation in the tumor suppressor gene. Mutagens can damage DNA and generate promutagenic lesions. This study aims to find out the loss of p53 gene functions due to mutation/polymorphism caused by genomic alteration and interaction with tobacco and its related ingredients in Pakistan. A total of 250 OSCC patient’s tissue and blood specimens were collected with informed consent from local hospitals of Karachi. The samples were compared with 250 age and sex matched controls. The OSCC was confirmed by histopathology of the tissue samples. Extraction of DNA from blood and tissue samples was carried out and 10 exons of p53 gene were amplified through polymerase chain reaction (PCR) by using forward and reverse primers. The amplified PCR products were checked by agarose gel electrophoresis, and PCR products were screened for mutation(s) by single stranded conformational polymorphism (SSCP). The PCR-SSCP analyses showing mobility shift bands indicated the single nucleotide mutation/polymorphism in tissue and blood samples of the patients. A single nucleotide change on SSCP gels was observed in the coding region of exon 2, 3, 4, 5, 6, 7, 10 and 11. The change was significantly higher in the tissue samples of the OSCC patients but not in their blood. The change of single nucleotide may be responsible for the substitution of amino acid in the p53 protein. This may result in the germ line mutation(s) of the p53 gene due to chewing habits which are involved in different steps of tumorigenesis and increasing the susceptibility of OSCC in Pakistan.
A non-random deletion in the p53 gene in oral squamous cell carcinoma
British journal of cancer, 1996
In a retrospective study of the mutational spectrum of the p53 gene in oral squamous cell carcinoma, 80 primary tumours diagnosed in 1980-90 were included. Using polymerase chain reaction/single strand conformation polymorphism (PCR/SSCP) analysis 47 mutations were found distributed in 39 of the tumours (49%). Unexpectedly, the majority of the mutations (29/47; 62%) were found in exon 8, and at sequencing 17 of them showed a 14 bp deletion in codons 287-292, causing formation of a stop codon and accordingly a truncated protein lacking the C-terminal. The majority of the patients with the 14 bp deletion were women (13/17), and it seemed as though certain potential risk factors for carcinoma of the head and neck were less common in this group.
Frequency of p53 gene mutation and protein expression in oral squamous cell carcinoma
Journal of the College of Physicians and Surgeons--Pakistan : JCPSP, 2014
To determine the frequency of p53 gene mutation and protein expression in Oral Squamous Cell Carcinoma (OSCC) and to establish correlation between the two. Analytical study. Histopathology Department and Molecular Biology Laboratory, Armed Forces Institute of Pathology (AFIP), Rawalpindi, from May 2010 to May 2011. Thirty diagnosed cases of OSCC were selected by consecutive sampling. Seventeen were retrieved from the record files of the AFIP, and 13 fresh/frozen sections were selected from patients reporting to the Oral Surgery Department, Armed Forces Institute of Dentistry (AFID). Gene p53 mutation was analyzed in all the cases using PCRSSCP analysis. DNA was extracted from the formalin-fixed and paraffin-embedded tissue sections and fresh/frozen sections. DNA thus extracted was amplified by polymerase chain reaction. The amplified products were denatured and finally analyzed by gel electrophoresis. Gene mutation was detected as electrophoretic mobility shift. The immunohistochemi...
Mutation status of p53 gene in oral squamous cell carcinoma
Stomatoloski glasnik Srbije, 2009
Introduction p53 gene is the most common tumor suppressor gene involved in pathogenesis oral squamous cell carcinoma (OSCC). Protein product of p53 gene contributes to cell cycle control and apoptosis. p53 gene mutations may lead to uncontrolled cell growth. The aim of this study was to determine the incidence of mutation in DNA-binding domain of p53 gene.
Clinical Cancer Research, 2011
Purpose: LOH at the p53 locus has been reported to be associated with esophageal squamous cell carcinogenesis. The aim of this study is to identify potential mechanisms resulting in LOH around the p53 locus in its carcinogenesis. Experimental Design: We investigated 10 esophageal cancer cell lines and 91 surgically resected specimens, examining them for LOH at the p53 locus on chromosome 17. We examined the p53 gene by using microsatellite analysis, comparative genomic hybridization (CGH), FISH, and single-nucleotide polymorphism–CGH (SNP–CGH). Results: In an analysis of specimens by microsatellite markers, a close positive correlation was found between p53 mutations and LOH at the p53 locus (P < 0.01). Although four cell lines were found to be homozygous for p53 mutations, LOH at the p53 locus was not detected by CGH. Among two p53 mutant cancer cell lines and five p53 mutant/LOH cancer specimens analyzed by FISH, both the cell lines and four of the specimens exhibited no obviou...
British Journal of Cancer, 2005
The present study was designed to examine whether different p53 haplotypes of exon 4 -intron 3 -intron 6 affect the frequency of mutations and loss of heterozygosity (LOH) of the p53 gene in male oral squamous cell carcinomas (OSCCs) in Taiwan. We found that individuals without two Pro-W-G alleles had significantly higher frequency of p53 mutations than those with two Pro-W-G alleles (odds ratio (OR) ¼ 1.98; 95% confidence interval (CI), 1.10 -3.56). Out of the 172 p53 gene exon 4 informative male OSCCs, 72 (41.9%) showed LOH. Among these 72 OSCCs with LOH, the frequency of Pro allele loss was 73.6% (53/72). It is notable that alcohol drinking increased the frequency of Arg allele loss (OR ¼ 10.56; 95% CI, 1.23 -234.94) in OSCCs from patients who both smoked cigarettes and chewed areca quid (AQ). The frequency of LOH of p53 was not different between p53-mutated OSCCs and p53-normal OSCCs. Thus, the present study revealed that (a) the Arg allele is associated with p53 mutations, (b) the Pro allele is preferentially lost in OSCCs associated with cigarette smoking and AQ chewing, while the frequency of Arg allele loss is increased with alcohol drinking, and (c) haploinsufficiency of p53 is in itself likely to contribute to tumour progression in Taiwanese OSCCs.
European Journal of Translational Myology
Mutations in tumor suppressor p53 protein can occur at different phases of malignant transformation and affect the patient's prognosis. This study aimed to evaluate the expression of mutant p53 protein in Iranian patients with the primary and recurrence oral squamous cell carcinoma (OSCC). This retrospective cross-sectional study conducted on a group of patients with the primary OSCC (n=122) and the control subjects with oral noncancerous reactive lesions (n=80). Immunohistochemistry was performed with the DO-7 monoclonal antibody against p53 protein, and samples with ≥10% immunostaining were considered positive. Statistical analyses were carried out using SPSS. Positive staining for p53 was observed in none of the control subjects and 57.4% (70 of 122) of the primary OSCC patients (p<0.0001, OR=107.69, 95%CI=6.49-179.0). The p53 immunopositivity had no significant differences between males and females (54.2% vs. 62%, p=0.390), but significantly different between those aged b...
Determination of p53 genotypes in oral cancer patients from India
British journal of cancer, 2001
The p53 tumour suppressor gene is inactivated in various types of human cancers, and has been implicated as an early event in several cancers. A p53 Pro/Arg polymorphism at exon 4 codon 72, has been suggested to be involved in susceptibility to cancers as well. Hence, in the current study, we investigated p53 exon 4 codon 72 polymorphism using Proline or Arginine specific primers from the peripheral blood cells (PBC) representing constitutional DNA from 72 oral cancer patients. PBC from 153 normal healthy individuals were used to determine the frequency of the p53 genotypes, Pro/Pro, Arg/Arg and Pro/Arg, in the Indian population. The frequency of distribution of genotypes in the normal healthy individuals was, Pro/Pro - 0.20 (31/153), Arg/Arg -- 0.14 (22/153) and Pro/Arg -- 0.65 (100/153); and in the oral cancer patients was, Pro/Pro -- 0.19 (14/72), Arg/Arg -- 0.08 (6/72) and Pro/Arg -- 0.72 (52/72). Thus, we observed an equidistribution of the genotypes in normal control and oral ...
P53-PROTEIN Over-Expression and Gene Mutational of Oral Carcinoma In-Situ
Dental Journal (Majalah Kedokteran Gigi), 2007
We had been reported histological types of oral carcinoma in-situ (oral CIS), such as basaloid, verrucous, and acanthothic/ atrophic types. We considered that they have different histological appearance influenced by molecular behavior. To understand the molecular behavior of them we examined p53 exon 4-8 gene mutation and their protein expression. Using 35 cases formalin-fixed paraffin sections of oral CIS and 10 cases of mild and moderate squamous epithelial displasia (SED) as a control were subjected to p53 immunohistochemistry. In the next step all cases were subjected to p53 gene mutations analysis by laser capturing microdissection and direct sequencing of PCR product for exon 4-8. Showed that p53-protein over-expression were found in basal layer of SED and the p53 protein over-expression were confined in the whole layer of CIS-basaloid type, basal and parabasal layers of CIS-verrucous type, and sporadically in the basal layer of CIS-acanthothic type. Mutational analysis for p53 gene showed 43% of total cases of CIS had p53 gene mutation therefore CIS-basaloid type had mutations more frequently than the other types and mutation in exon 8 more dominant than other exons, which had some common mutation at codons 196, 248, 282, 291, and 306, while no particular mutations were found in control (SED).Our criteria to diagnose several types of oral carcinoma in-situ by p53 protein expression and mutational analysis could be used to understand molecular behavior of CIS.