Evaluation of the contribution of cyclooxygenase 2 genotypes to breast cancer in Taiwan

Abstract

Overexpression of cyclooxygenase 2 (COX-2) has been suggested to be associated with breast carcinogenesis. The aim of the present study was to evaluate the contribution of genotypic polymorphisms in COX-2 to breast cancer risk of Taiwanese females. In total, 1,232 breast cancer patients and 1,232 healthy controls were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methodology. Six polymorphic variants of COX-2, including G-1195A (rs689466), G-765C (rs20417), T8473C (rs5275), intron 1 (rs2745557), intron 5 (rs16825748) and intron 6 (rs2066826) were examined. The results showed that the GC genotype of COX-2, G-765C was associated with a lower risk compared to the wild-type GG genotype (odds ratio(OR)=0.66, 95% confidence interval(CI)=0.53-0.83, p=0.0005). The C allele of COX-2 G-765C was significantly more frequently found in controls than in cancer patients (p=0.0006). In addition, the OR of the GG/AG+AA, GC/GG and GC/AG+AA at G-765C/Intron 1 combined genotypes compared to wild-type GG/GG genotype were 0.79 (95%CI=0.66-0.96; p=0.0166), 0.61 (95%CI=0.48-0.78; p=0.0001), and 0.71 (95%CI=0.36-1.37; p=0.3040), respectively. As for the combination of G-765C and intron 6, the OR of the GG/AG+AA, GC/GG and GC/AG+AA combined genotypes compared with wild-type GG/GG reference genotype were 0.79 (95%CI=0.62-1.01; p=0.0561), 0.63 (95%CI=0.50-0.81; p=0.0003), and 0.68 (95%CI=0.38-1.21; p=0.1897), respectively. Our results indicate that the C allele of COX-2, G-765C was associated with a decreased risk of breast cancer in Taiwan, and could serve as an early detection and predictive marker for breast cancer risk.

Keywords: Breast cancer; COX-2; Taiwan; carcinogenesis; genotype; polymorphism.