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 machineryin mammalian cells. The encoded enzyme is a key to the base excision repair (BER) pathway. It is evident that polbeta has mutations in various cancer samples, but little is known about ovarian cancer. Aim: Identification of anyvariant form of polβ cDNA in ovarian carcinoma and determination of association between the polymorphismand 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 betais 1 kb. Our study of association between the variant and the endometrioid type shows that it is a statisticallysignificant factor for ovarian cancer [OR=31.9 (4.12-246.25) with p<0.001]. The association between variantand 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 andvariant/endometrioid of 0.44 and 0.39).
Conclusion: Individuals from this part of India with this type of variantmay be at risk of stage IV, endometrioid type ovarian carcinoma.