UDP-glucuronosyltransferase and sulfotransferase polymorphisms, sex hormone concentrations, and tumor receptor status in breast cancer patients

INTRODUCTION: UDP-glucuronosyltransferase (UGT) and sulfotransferase (SULT) enzymes are involved in removing sex hormones from circulation. Polymorphic variation in five UGT and SULT genes – UGT1A1 ((TA)(6)/(TA)(7)), UGT2B4 (Asp(458)Glu), UGT2B7 (His(268)Tyr), UGT2B15 (Asp(85)Tyr), and SULT1A1 (Arg(213)His) – may be associated with circulating sex hormone concentrations, or the risk of an estrogen receptor-negative (ER(-)) or progesterone receptor-negative (PR(-)) tumor. METHODS: Logistic regression analysis was used to estimate the odds ratios of an ER(- )or PR(- )tumor associated with polymorphisms in the genes listed above for 163 breast cancer patients from a population-based cohort study of women in western Washington. Adjusted geometric mean estradiol, estrone, and testosterone concentrations were calculated within each UGT and SULT genotype for a subpopulation of postmenopausal breast cancer patients not on hormone therapy 2–3 years after diagnosis (n = 89). RESULTS: The variant allele of UGT1A1 was associated with reduced risk of an ER(- )tumor (P for trend = 0.03), and variants of UGT2B15 and SULT1A1 were associated with non-statistically significant risk reductions. There was some indication that plasma estradiol and testosterone concentrations varied by UGT2B15 and SULT1A1 genotypes; women with the UGT2B15 Asp/Tyr and Tyr/Tyr genotypes had higher concentrations of estradiol than women with the Asp/Asp genotype (P = 0.004). Compared with women with the SULT1A1 Arg/Arg and Arg/His genotypes, women with the His/His genotype had elevated concentrations of testosterone (P = 0.003). CONCLUSIONS: The risk of ER(- )breast cancer tumors may vary by UGT or SULT genotype. Further, plasma estradiol and testosterone concentrations in breast cancer patients may differ depending on some UGT and SULT genotypes.