Single Nucleotide Polymorphisms (SNPs) of OGG1 (Ser326Cys) and APE1 (Asp148Glu; –141T/G) Genes and Breast Cancer Risk in Filipino Women

Base excision repair (BER) pathway involves repair of damaged DNA caused by spontaneous decay of DNA, reactive oxygen species, and ionizing radiation. Polymorphisms of genes involved in the pathway have been reported to be associated with cancer risk. In this study, the association of BER gene polymorphisms with breast cancer risk in Filipino women was assessed. The polymorphisms studied included X-ray repair cross-complementing group 1 (XRCC1, Arg399Gln), 8-oxoguanine DNA glycosylase (OGG1, Ser326Cys), and apurinic/apyrimidinic endonuclease 1 (APE1, Asp148Glu; –141T/G). A total of 186 participants (93 breast cancer cases and 93 breast cancer-free control) were recruited for the study. The genotyping of samples was performed using polymerase chain reaction with confronting two-pair primers (PCR-CTPP). The association of polymorphisms of BER genes with breast cancer risk and gene-environment interaction was determined using the unconditional logistic regression model. Distributions of OGG1 and APE1 genotypes were in Hardy-Weinberg equilibrium (HWE); however, XRCC1 genotype distribution deviated from HWE and was not further analyzed. The analysis showed that OGG1 Ser326Cys, APE1 Asp148Glu, and APE1 –141T/G had no significant association with breast cancer risk. Also, there is no significant interaction between the three BER gene variants and family history of cancer. Lastly, no significant increased risk was observed when the combined effects of risk alleles of the three BER gene variants were determined. In conclusion, the study suggests that OGG1 Ser326Cys, APE1 Asp148Glu, and APE1 –141T/G are not good indicators of breast cancer risk in Filipino women.