Context: Several factors contribute to the increase in breast cancer (BC) incidence, such as lifetime exposure to estrogen, early menarche and older ages at first birth, menopause, and the increased prevalence of postmenopausal obesity. In fact, there is an association between an increased BC risk and elevated estrogen levels, which may be involved in carcinogenesis via the estrogen receptor alpha (ERα) encoded by the ESR1 gene. Interestingly, there is an antagonistic relationship between ERα and the aryl hydrocarbon receptor (AhR) in BC cells.
Aims: Herein, we explore the combined effects of the ESR1 (XbaI, PvuII) and AhR polymorphisms on BC development in Mexican women according to their menopausal status.
Settings and design: Investigation was performed using a cases and controls design.
Subjects and methods: In a group of 96 cases diagnosed with BC and 111 healthy women, the single-nucleotide polymorphisms ESR1 (XbaI, PvuII) and AhR gene were identified by qPCR.
Statistical analysis used: Chi-square test or Fisher's exact test were used. Statistical analyses were conducted using the STATA statistical package (Version 10.1, STATA Corp., College Station, TX, USA).
Results: The G/G XbaI genotype was more prevalent in the cases than in the controls (P = 0.008). Moreover, Mexican women carrying the XbaI (wild type [WT]/G or G/G) ESR1 genotype have higher risk (12.26-fold) for developing postmenopausal BC than individuals carrying the WT/WT genotype.
Conclusions: The presence of the G/G genotype of XbaI may be considered a susceptibility allele in Mexican women. Due to increased postmenopausal BC risk, the XbaI (WT/G or G/G) alleles may be used as a postmenopausal predictive factor for BC in Mexican women.
Keywords: Aryl hydrocarbon receptor polymorphisms; ESR1polymorphisms; Mexican population; menopausal status.