Tumor protein 53 gene polymorphism, demographic attributes and associated risk factors among liver cancer patients in Calabar, Nigeria

Mutations in the TP53 gene had been attributed to the development of liver cancer. Hepatocellular carcinoma (HCC) and liver tumour are liver diseases having high mortality rates in several populations. There is no information on the TP53 gene polymorphism among liver diseases patients in Calabar, Nigeria. This study investigated the genetic polymorphism of TP53 among HCC and liver tumour in Calabar. This research was carried out in the University of Calabar Teaching Hospital, Calabar. Blood samples were collected from 35 clinically diagnosed hepatocellular carcinoma and 10 tumour patients and 10 healthy controls. DNA was extracted from all blood samples and Polymerase Chain Reaction (PCR) was performed using specific primers. The PCR amplicons were digested using Hae III restriction enzyme and the genotypic and allelic frequencies was determined. Demographic data among participants showed that males were 68.9% (31), females (31.1%; 14), sex ratio (2.2: 0.5), mean age was 41.51 ± 2.13 years with an odds ratio of 1.25. The distribution of participants according to marital status were 33(73.3%), 10(22.2%), and 2(4.4%) for married, single, and widowed respectively. The participants were from different extractions with varied representations of Yakurr (22.2%, 10), Efik (20%, 9), Boki (13.3%, 6), Ogoja (13.3%, 6), Annang (8.8%, 4), Ibibio (2.2%, 1) and Igbo (2.2%, 1) and respectively. Approximately, 64.7% (30) of the chronic liver diseases were from the Central and Northern part of Cross River State. The risk factors were HCV infection, HBsAg+, alcoholism, smoking, consumption of groundnuts that may have been contaminated with aflatoxin and family history of the disease. PCR product yielded 254 bp and digested PCR product showed homozygous TT mutation (27), heterozygous GT mutation (17) and homozygous GG wild type (1) in cases. The overall TP53 gene mutation frequency was 46.32% (44). The frequency of G allele, T allele, GG, GT and TT were 0.21, 0.79, 0.04, 0.33 and 0.62 respectively among cases, while GG (wild type) was only detected among controls in the study population. The genotypic and allelic frequencies conform to Hardy-Weinberg equilibrium meaning that the forces of evolution were not acting on the locus. There were significant differences in the genotypic proportions of the TP53 gene polymorphism among patients and controls. This study on the TP53 gene polymorphism will serve as baseline information on the molecular etiology of hepatocellular carcinoma and liver tumour in Cross River State.

In search of TP53 mutational hot spots for Li-Fraumeni syndrome in Asian populations

OBJECTIVE

Germline mutations of the TP53 tumour suppressor gene are the only known cause of the hereditary autosomal disorder called Li-Fraumeni syndrome (LFS). However, little information is available about TP53 pathogenic variants in Asian LFS patients, making it difficult to provide precise genetic counselling with regard to long-term cancer risk. We conducted a systematic review to gather relevant case-control studies exploring the association between TP53 polymorphisms and the incidence of cancer belonging to the LFS spectrum in Asian populations.

METHOD

Systematic review and meta-analysis. The odds ratio was used as a summary effect measure to quantify the strength of the association between TP53 polymorphisms and cancer risk by means of random-effects meta-analysis.

RESULTS

In total, 16 studies were included in this systematic review, with 13 studies (involving 10,645 cases and 28,288 controls) that enabled meta-analysis. The majority of the studies focused on a single-nucleotide variation at codon 72 in exon 4 (c.215C>G, p.Arg72Pro, rs1042522). Therefore, we tested either dominant, co-dominant, recessive, or heterozygous models and found that the p.Arg72Pro was not significantly associated with increased cancer risk in any of the models.

CONCLUSION

We found the number of studies on cancers belonging to the LFS spectrum in Asia is very small. Thus, at the present time a meta-analysis approach is somewhat useful to identify germline TP53 mutations as potential markers of hereditary cancer associated with LFS in Asian populations.

A meta-analysis and in silico analysis of polymorphic variants conferring breast cancer risk in the Indian subcontinent

Background: Genetic association studies on breast cancer on the Indian subcontinent have yielded conflicting results, and the precise effect of these variants on breast cancer pathogenesis is not known. Methods: Genomic variants, as obtained from selected studies from the Indian subcontinent, were subjected to random-effects and fixed-effect meta-analysis. Functional annotation of the relevant variants was done through a tried and tested in silico pipeline. Results: We found rs4646903/CYP1A1, rs1799814/CYP1A1, rs61886492/GCPII, del2/GSTM1, rs4680/COMT and rs1801394/MTRR to be associated with breast cancer. The del2/GSTM1 holds the association in premenopausal women. Conclusions: This is the first study of its kind from the Indian subcontinent analysing the extent of association of variants across populations followed by their functional annotation in the disease pathway.

Mutation profiling in the PIK3CA, TP53, and CDKN2A genes in circulating free DNA and impalpable breast lesions

Breast impalpable lesions have become a clinical dilemma because they are small, presenting a heterogeneous cellular phenotype. The aim of this study was to evaluate the mutational profile of the PIK3CA, TP53, and CDKN2A genes, comparing the mammary tissue with the respective circulating free DNA (cfDNA). The PIK3CA, TP53, and CDKN2A genes were sequenced (PCR-Sanger) in 58 women with impalpable lesions (49 malignant and 9 benign) with the respective cfDNA. The chi-square or Fisher's exact test was used to evaluate statistical significance between the clinical variables and mutational profile. A total of 51 out of 58 samples generated successful mutation profiles in both breast lesion and cfDNA. Of the 37 mutations detected, 10 (27%) and 16 (43%) mutations were detected in benign and malignant breast lesions, respectively, while 2 (5%) and 9 (24%) were found in cfDNA of women with benign and malignant lesions, respectively. The lymph node involvement with mutations in the PIK3CA in malignant lesions (P = 0.001), and the relationship between mutations in PIK3CA, comparing ductal tumors with benign lesions (P = 0.05), were statistically significant. This study detected different mutations in PIK3CA, TP53, and CDKN2A genes, which represent, in part, the heterogeneity of impalpable lesions. The results confirm that more studies should be conducted on the functional role of cfDNA in the impalpable lesions.

Impact of p53 arg72pro SNP on Breast Cancer Risk in North Indian Population

Background:

Genetic changes in p53 gene contribute to breast cancer susceptibility.

Objective and Methods:

A case-control study and a meta-analysis were performed to investigate the role of p53 codon72 SNP with breast cancer susceptibility in Indian women.

Results:

p53 heterozygous arginine variant was associated with decreased risk of breast cancer in total cohort. In meta-analysis, Allelic and GG vs. CC genetic comparison model were found to be associated with breast cancer risk. Moreover, recessive comparison model indicated a protective correlation with breast cancer occurrence.

Conclusion:

The findings of our case-control study and meta-analysis suggest a significant association between p53 Arg72Pro polymorphism and an increased risk of breast cancer in Indian population.

The Evaluation of p53 Polymorphism at Codon 72 and Association With Breast Cancer in Iran: A Systematic Review and Meta-analysis

Background

Breast cancer is the most common cancer among women in Iran and the world. Multiple environmental factors and genetic variations such as genetic polymorphisms are of its main causes. p53 gene plays an important role in conserving and sustaining the genome as a tumor suppressing gene. Change and polymorphism at codon 72 of p53 gene are correlated with increased risk of lung, mouth, endometrial, prostate, and colorectal cancers, and could be considered an indicator of susceptibility to breast cancer.

Methods

Twelve studies (1,190 cases and 1,145 control studies with evaluation of three types of Arg/Arg, Arg/Pro, and Pro/Pro genotypes) have been conducted using keywords, such as polymorphism at codon 72, gene p53 polymorphisms, and the relation between polymorphisms and breast cancer, from databases in Iran, including Magiran, Medlibe, Sid, and Iranmedex, as well as Latin databases such as PubMed, Google Scholar, Science Direct, and Scopus.

Results

The OR for Arg/Arg is 1.58 (95% CI: 2.45 to 1.01), the OR for Arg/Pro is 0.75 (95% CI: 1.10 to 0.51), and the OR for Pro/Pro is 0.62 (95% CI: 0.93 to 0.42). p53 gene polymorphism at codon 72 is statistically significant in Arg/Arg and Pro/Pro genotypes.

Conclusions

Arg/Arg genotype can be considered as a risk factor for breast cancer, and Pro/Pro genotype can be accounted for as a protective factor against breast cancer.

Association of p53 codon 72 polymorphism and survival of North Indian lung cancer patients treated with platinum-based chemotherapy

p53 helps in maintaining genomic stability by undergoing cellular arrest, DNA repair or cellular apoptosis during DNA damage. So, as to find the association of p53Arg 72 Pro towards lung carcinogenesis and overall survival of North Indian lung cancer patients, single nucleotide polymorphic variant (rs1042522) was analyzed. 840 subjects including 420 cases and 420 controls were recruited and genotyped using PCR-RFLP technique for p53Arg 72 Pro polymorphic site. Association was analyzed using adjusted odds ratio along with its confidence intervals (95 % CI) and p value predicted from logistic regression whereas overall survival for lung cancer patients was obtained using Kaplan-Meir and Cox regression model for different parameters to obtain hazard ratio and survival time with statistical significance (log-rank p value). None of the variant genotypes for p53Arg 72 Pro showed any association towards lung cancer risk or any specific histological subtype. Lung cancer subjects with Pro/Pro genotype had better median survival time as compared to Arg/Pro genotype (10 months; HR = 0.65; 95 % CI = 0.45-0.95; p = 0.03). Furthermore, female lung cancer patients with Arg/Pro (HR = 0.08; 95 % CI = 0.02-0.34; p = 0.0005) and Pro/Pro (HR = 0.21; 95 % CI = 0.06-0.67; p = 0.008) genotypes showed a better overall survival and hence a better prognosis as compared to males. Our data also reveals that lung cancer patients with ECOG scores between 0 and 1 and carrying the Pro/Pro had better chances of survival. p53 codon 72 polymorphism could play a role as a prognostic marker in lung cancer patients.

Co-expression of ING4 and P53 enhances hypopharyngeal cancer chemosensitivity to cisplatin in vivo

Hypopharyngeal cancer is a distinct type of malignant head and neck tumor, which exhibits low sensitivity to anti-cancer drugs. The importance of developing methods for reducing chemotherapy resistance, and improving and enhancing prognosis has previously been emphasized and is considered a challenge for effective clinical treatment of hypopharyngeal cancer. The current study investigated the effects of co-expression of inhibitor of growth protein 4 (ING4) and P53, a tumor suppressor gene, on chemosensitivity to cisplatin in human hypopharyngeal cancer xenografts in vivo, and the potential molecular mechanisms involved. A tumor model was established by injecting athymic nude mice with FADU human hypopharyngeal cancer cells. Five days after intratumoral and peritumoral injections of an empty adenoviral vector (Ad), Ad-ING4-P53, cisplatin, or a combination of Ad-ING4-P53 and cisplatin (Ad-ING4-P53 + cisplatin) every other day for 5 days, the mice were euthanized and their tumors, livers, and kidneys were removed. The tumor weights were used to calculate the inhibition rate, and the expression levels of ING4 and P53 were detected by reverse transcription-polymerase chain reaction. Additionally, apoptotic cells were detected using terminal deoxynucleotidyl transferase dUTP nick end labeling, and immunohistochemistry determined the levels ING4, P53, B-cell lymphoma-2 (Bcl-2) and Bcl-2 associated X protein (Bax) protein expression. The results demonstrated increased expression of ING4 and P53 in the Ad-ING4-P53 groups compared with PBS and Ad groups, indicating successful introduction of the genes into the tumor cells. Notably, the Ad-ING4-P53 + cisplatin group exhibited a higher inhibition rate compared with the four other groups. The results of immunohistochemistry analysis demonstrated that Bax expression was increased and Bcl-2 was decreased in the Ad-ING4-P53 + cisplatin group. This suggested that the enhanced cisplatin chemosensitivity with Ad-ING4-P53 gene therapy in hypopharyngeal cancer xenografts may be associated with apoptosis induction through upregulation of Bax expression and downregulation of Bcl-2. The results of the present study indicated that gene therapy combined with cisplatin treatment may be a promising treatment for human hypopharyngeal cancer.

Clinical significance of TP53 (R72P) and MDM2 (T309G) polymorphisms in breast cancer patients

INTRODUCTION

TP53 gene is the most frequently altered tumor suppressor gene in breast cancer. It has been observed that MDM2 plays a central role in regulating the TP53 pathway. This study aimed to investigate the role of TP53 Arg72Pro and MDM2 T309G polymorphisms in breast cancer patients.

MATERIAL AND METHOD

The TP53 (Arg72Pro) and MDM2 (T309G) polymorphisms were studied in a hospital-based case control study by AS-PCR in 100 breast cancer patients and 100 healthy control subjects.

RESULTS

It was observed that TP53 Arg72Pro polymorphism was significantly associated with breast cancer (χ (2) = 9.92, p = 0.007). A significantly increased breast cancer risk was associated with the Proline allele [odds ratio 1.84 (95 % CI: 1.22-2.77), risk ratio 1.34 (95 % CI: 1.11-1.63), p value 0.003], HER2/neu status (p = 0.01) and distant metastasis (p = 0.05). On the other hand, we have found a significant correlation between MDM2 (T309G) polymorphism with HER2/neu status (χ (2) = 11.14, p = 0.003) and distant metastasis (p value = 0.04).

CONCLUSION

Our finding suggests that TP53 (Arg72Pro) polymorphism may play a significant role as risk factor for breast cancer in north Indian breast cancer patients. While MDM2 (T309G) polymorphism may not be directly associated with the risk of breast cancer occurrence in the same population, but it may play role in disease progression by triggering TP53.

Lack of influence of TP53 Arg72Pro and 16bp duplication polymorphisms on risk of breast cancer in Iran

TP53 is assumed to be a very important tumour suppressor gene, as illustrated by recent reports that have shown effects of its polymorphisms on breast cancer risk. Arg72Pro and PIN3(16bp duplication) polymorphisms are proposed to have an effective role in structural changes of p53 and have therefore attracted interest as a risk factor for breast cancer in different populations. The aim of this study was to examine and determine whether p53 codon 72 and PIN3 Ins16 bp may be associated with an increased risk for breast cancer in female patients from the northwest of Iran. Genotyping was performed by PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism) method for a total of 100 women with breast cancer and 100 healthy women without any background of cancer, focusing on the TP53 Arg72Pro-16Del/Ins haplotypes and the combined genotypes. The results in this study established no statistical significant distinctions between the genotypes and allele frequency were found for Arg72Pro and PIN3 Ins 16 bp polymorphisms between patients and controls.

Breast cancer risk in relation to TP53 codon 72 and CDH1 gene polymorphisms in the Bangladeshi women

Pharmacogenomic studies play a significant role in understanding the risk of breast cancer where genetic abnormalities are implicated as the etiology of cancer. Various polymorphisms of tumor suppressor gene TP53 and E-cadherin (CDH1) have been found to be associated with increased breast cancer risk worldwide. This study aimed to analyze the contribution of TP53 and CDH1 gene anomalies in breast cancer risk in the Bangladeshi breast cancer patients. For risk determination, 310 patients with breast cancer and 250 controls from Bangladeshi women were recruited who are matched up with age and use of contraceptives with patients. Genetic polymorphisms were detected by using polymerase chain reaction restriction fragment length polymorphism. A significant association was found between TP53Arg72Pro (rs1042522) and CDH1 -160 C/A (rs16260) polymorphisms and breast cancer risk. In case of P53rs1042522 polymorphism, Arg/Pro (P = 0.0053, odds ratio (OR) = 1.69) and Pro/Pro (P = 0.018, OR = 1.83) genotypes were associated with increased risk of breast cancer in comparison to the Arg/Arg genotype. Arg/Pro + Pro/Pro genotype and Pro allele also increased the risk of breast cancer (P = 0.002, OR = 1.73; P = 0.004, OR = 1.43, respectively). In case of CDH1rs16260 polymorphism, C/A heterozygote and combined C/A + A/A genotypes were found to be strongly associated (P = 0.005, OR = 1.67; P = 0.0037, OR = 1.68) with increased risk of breast cancer. The variant A allele also increased the breast cancer risk (P = 0.0058, OR = 1.52). The present study demonstrates that P53Arg72Pro and CDH1rs16260 polymorphisms are associated with elevated breast cancer risk in the Bangladeshi population.

No Evidence of Association of the Arg72Pro p53 Gene Polymorphism with Cancer Risk in the Saudi Population: a Meta-Analysis

BACKGROUND

Earlier studies on the association between p53 codon 72 Arg>Pro polymorphism and cancer risk were inconclusive and conflicting for the Saudi population. Therefore, we performed a meta-analysis to investigate the relationship between the codon 72 Arg>Pro polymorphism and overall cancer risk in Saudi Arabia.

MATERIALS AND METHODS

We searched all eligible published studies and data were pooled together to perform the meta-analysis. Pooled odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated for homozygous, heterozygous, dominant and recessive genetic models.

RESULTS

A total of five eligible published studies covering 502 cancer cases and 784 healthy controls were included in the meta-analysis. No publication bias was detected in this study. The results suggested that the variant (Pro vs Arg: p=0.960; OR=1.004, 95% CI=0.852-1.183), homozygous (Pro.Pro vs Arg.Arg: p=0.970; OR=1.006, 95% CI=0.729-1.390), heterozygous (Arg.Pro vs Arg.Arg: p=0.473; OR=0.783, 95% CI=0.402-1.527) carriers were not associated with overall cancer risk. Similarly, dominant (Pro.Pro+Pro.Arg vs Arg.Arg: p=0.632; OR=0.886, 95% CI=0.540-1.454) and recessive (Pro.Pro vs Pro.Arg+Arg.Arg: p=0.269; OR=1.163, 95%CI=0.890-1.521) models also did not indicate increased risk of cancer.

CONCLUSIONS

The current meta-analysis suggests that the codon 72 Arg>Pro polymorphism of the p53 gene might not contribute to cancer susceptibility in Saudi population. Future well designed large case control studies are needed to validate our findings.

TP53 polymorphisms in sporadic North Indian breast cancer patients

BACKGROUND

The purpose of this study was to evaluate the potential association of five (p.P47S, p.R72P, PIN3 Ins16bp, p.R213R and r.13494g>a) polymorphisms of TP53 with the risk of developing breast cancer in North Indian Punjabi population.

METHODS

We screened DNA samples of 200 sporadic breast cancer patients (197 females and 3 males) and 200 unrelated healthy, gender and age matched individuals for the polymorphisms.

RESULTS

For the p.P47S polymorphism, we observed the PP genotype in 99.5% of the patients and PS genotype in only 1 patient. All the controls had the wild type PP genotype. The frequency of RR, RP and PP genotype of p.R72P was 23.5% vs 33.5%, 51.5% vs 45.5% and 25% vs 21% in patients and controls respectively. Heterozygous (RP) genotype was increased in breast cancer patients as compared to controls (51.5 vs 45.5%) and showed 1.61 fold significantly increased risk for breast cancer (OR=1.61, 95% CI, 1.01-2.58, p=0.04). In breast cancer patients the frequencies of A1A1, A1A2 and A2A2 genotypes of PIN3 Ins16bp polymorphism were 67%, 26% and 7% respectively whereas in controls the genotype frequencies were 68.5%, 27.5% and 4% respectively, with no significant difference. For p.R213R (c.639A>G), all individuals had homozygous wild type genotype. The frequencies of GG, GA and AA genotypes of TP53 r.13494g>a polymorphism were 62 vs 67.5%, 33 vs 28% and 5 vs 4.5% in patients and controls respectively, again without significant difference. We observed that RP- A1A1 genotype combination of p.R72P and PIN3 Ins16bp and RP-GG combination of p.R72P and r.13494g>a polymorphism showed significant risk of breast cancer (OR=1.65, 95%CI: 0.98-2.78, p=0.05; OR=1.72, 95%CI: 1.01-2.92, p=0.04).

CONCLUSION

The results of present study indicated that among the five TP53 polymorphisms investigated, the p.R72P polymorphism, and the RP-A1A1 and RP-GG genotype combination contribute to breast cancer susceptibility in North Indians.

Lack of association of intron 3 16 bp polymorphism of TP53 with breast cancer among Iranian-Azeri patients

BACKGROUND

p53 gene is a well-known tumor suppressor gene that has several polymorphisms in both its exons and introns. It has been suggested that intron 3 16 bp duplication polymorphism may affect the gene function resulting in reduction or suppression of p53 anti tumor activity. In most case control studies a duplicated allele has been noticeably more frequent in cases rather than controls but there are also conflicting results. The aim of this study was to assess the association of intron 3 16 bp duplication polymorphism of p53 with breast cancer risk among Iranian-Azeri population. We also analyzed the clinicopathological information of patients as an epidemiological description of breast cancer in the north-west of Iran.

MATERIALS AND METHODS

This case-control study was performed on 221 breast cancer patients and 170 controls. Genomic DNA was extracted from peripheral blood samples and tumor tissues. p53 PIN3 genotype was determined using electrophoresis of PCR products on 8% non-denaturing polyacrylamide gels and silver staining.

RESULTS

In the control and case groups, respectively, 62.9% and 61.1% had no 16 bp insertion (A1A1 genotype), 7.1% and 7.7% had insertion in both p53 alleles (A2A2) and 30% and 31.2% were heterozygous (A1A2). There was no significant difference between genotype frequencies as well as allelic frequencies in two case and control groups.

CONCLUSIONS

According to the result of the present study, the intron 3 16 bp duplication polymorphism of p53 could not be assessed as a marker of risk factor for predisposition to breast cancer in Azeri population. However, a high frequency of A2 allele (22.1%) in our population suggested that intron 3 16 bp duplication polymorphism may be a valuable marker for study in other cancers with well designed large groups.

Association of TP53 PIN3 polymorphism with breast cancer in Moroccan population

TP53 is a tumor suppressor gene involved in cell cycle progression control, DNA damage repair, genomic stability, and apoptosis. Some polymorphisms in this gene have been associated with the development of a number of cancers including breast carcinoma. PIN3 Ins16bp polymorphism has been widely studied in different populations for an association with breast cancer risk. In most case-control studies, a duplicated allele has been more frequent in cases rather than controls but there are also inconsistent results. The present study aimed to assess the association of PIN3 Ins16bp polymorphism of p53 with breast cancer risk in Moroccan population. This case-control study was performed on 105 female patients with confirmed breast cancer and 114 healthy controls. The genotype frequency was 69.5 % (A1A1), 26.7 % (A1A2), and 3.8 % (A2A2) in patients and 68.4 % (A1A1), 24.6 % (A1A2), and 7 % (A2A2) in controls. No statistically significant association was observed between PIN3 Ins16bp polymorphism and breast cancer risk with odds ratio of 1.07 (confidence interval (CI) = 0.58-1.97, p = 0.83) for the heterozygous A1A2 and 0.53 (CI = 0.15-1.85, p = 0.32) for mutated homozygous A2A2.According to our preliminary genetic analysis, PIN3 Ins16pb polymorphism could not be assessed as a marker of risk factor for predisposition to breast cancer in Moroccan population. However, a high frequency of A2 allele (19.3 %) in our population suggested that PIN3 Ins16pb polymorphism may be a valuable marker for study in other cancers with larger groups.

Assessment of changes in the BRCA2 and P53 genes in breast invasive ductal carcinoma in northeast Brazil

Background

BRCA protein interacts with at least 13 different proteins that have been implicated with cancer susceptibility and loss of BRCA function is correlated to sensitivity to DNA crosslinking agents in preclinical models.

Results

BRCA2 methylation frequency was 44%, p53 Pro22 allele frequency was 32% and heterozygous frequency of Arg/Pro72 genotype was 60% which could be associated as risk factor for metastasis (p = 0.046 OR = 4.190). Regarding to polymorphism of codon 249 the frequency of Arg249 allele presented 82% which was considered not statistically significant.

Conclusions

There was not statistical significance to BRCA2 promoter methylation with any parameters chosen. However, our findings suggest that patients who present heterozygous genotype at codon 72 of p53 gene may have a major susceptibility to any type of metastasis and this could serve as potential auxiliary biomarker for poor prognosis.

Detection of TP53 R249 Mutation in Iranian Patients with Pancreatic Cancer

The TP53 gene encodes tumor protein p53 which play a major role in the etiology of pancreatic cancer. The important role of codon 249 of TP53 for binding of p53 to its sequence-specific consensus site in DNA has been revealed by crystallography's studies, and mutation at this codon was detected in the plasma of some human cancers. The TP53 Mut assessor software within the International Agency for Research on Cancer (IARC) TP53 Database was performed to evaluate every possible mutation at codon 249. DNA was extracted from the plasma of 133 pancreatic cancer patients and 85 noncancer-bearing individuals. Exon 7 in TP53 was amplified, and mutation at R249 was identified by the endonuclease cleavage of HaeIII. The group of patients showed a frequency of 11% (22 of 133 samples) R249 mutation compared to 3.5% (3 of 85 samples) in the group of control which was significant (P = 0.03). This mutation demonstrated statistically significant association with pancreatic cancer risk in unadjusted odds ratio (OR: 3.74, 95% CI: 1.1–13.2; P = 0.041); however when adjusted for confounding factors, it was marginally significant because of lower control samples. These findings demonstrate that mutation at R249 of TP53 can be considered for increasing risk of pancreatic cancer that needs more research.

Association of a newly identified variant of DNA polymerase beta (polβΔ63-123, 208-304) with the risk factor of ovarian carcinoma in India

BACKGROUND

DNA polymerase is a single-copy gene that is considered to be part of the DNA repair machinery in mammalian cells. The encoded enzyme is a key to the base excision repair (BER) pathway. It is evident that pol beta has mutations in various cancer samples, but little is known about ovarian cancer.

AIM

Identification of any variant form of polβ cDNA in ovarian carcinoma and determination of association between the polymorphism and ovarian cancer risk in Indian patients. We used 152 samples to isolate and perform RT-PCR and sequencing.

RESULTS

A variant of polymerase beta (deletion of exon 4-6 and 11-13, comprising of amino acid 63-123, and 208-304) is detected in heterozygous condition. The product size of this variant is 532 bp while wild type pol beta is 1 kb. Our study of association between the variant and the endometrioid type shows that it is a statistically significant factor for ovarian cancer [OR=31.9 (4.12-246.25) with p<0.001]. The association between variant and stage IV patients further indicated risk (χ2 value of 29.7, and OR value 6.77 with 95% CI values 3.3-13.86). The correlation study also confirms the association data (Pearson correlation values for variant/stage IV and variant/endometrioid of 0.44 and 0.39).

CONCLUSION

Individuals from this part of India with this type of variant may be at risk of stage IV, endometrioid type ovarian carcinoma.