Reduction in breast cancer susceptibility due to XbaI gene polymorphism of alpha estrogen receptor gene in Jordanians

Breast cancer is a global health concern among women worldwide. Estrogen receptor alpha (ERα) mediates diverse polymorphic effects in breast tissues that may relate to breast cancer susceptibility. The aim of this study was to evaluate the effect of -397 PvuII (T/C) and -351 XbaI (A/G) restriction fragment length polymorphism within intron 1 of ERα, and its effect on breast cancer susceptibility. A total of 156 women who were histopathologically diagnosed with breast cancer and 142 healthy Jordanian women were enrolled in this case-control study. Genomic DNA was extracted from whole peripheral blood, and the desired fragment was amplified using polymerase chain reaction followed by restriction digestion with PvuII and XbaI restriction enzymes. The results showed no significant association between PvuII polymorphism and breast cancer risk. However, a significant association was found between XbaI polymorphism and reduction in breast cancer risk within the "x" allele of heterozygotes (odds ratio [OR] 0.199, 95% confidence interval [CI] 0.09-0.044) and heterozygotes (OR 0.208, 95% CI 0.09-0.047). The combined analysis of PvuII and XbaI polymorphisms revealed a synergistic effect of Pp/Xx and pp/xx genotypes and a significant reduction in breast cancer risk with these genotypes. The results also showed no statistical differences among PvuII or XbaI polymorphisms based on stage, ER, progesterone receptor and expression of hormone receptor such as human epidermal growth factor receptor 2. This case-control study showed that XbaI polymorphism of alpha estrogen gene modified and reduced breast cancer susceptibility among Jordanians.