TY - JOUR T1 - The <em>MTHFR</em> C677T Polymorphism, Estrogen Exposure and Breast Cancer Risk: A Nested Case-control Study in Taiwan JF - Anticancer Research JO - Anticancer Res SP - 3863 LP - 3868 VL - 24 IS - 6 AU - WEI-YU LIN AU - YU-CHING CHOU AU - MEI-HSUAN WU AU - HAN-BIN HUANG AU - YI-LIN JENG AU - CHO-CHIEH WU AU - CHENG-PUNG YU AU - JYH-CHERNG YU AU - SAN-LIN YOU AU - TANG-YUAN CHU AU - CHIEN-JEN CHEN AU - CHIEN-AN SUN Y1 - 2004/11/01 UR - http://ar.iiarjournals.org/content/24/6/3863.abstract N2 - Background: We evaluated the effects of the MTHFR C677T polymorphism and its interaction with estrogen exposure on breast cancer risk in a nested case-control study conducted in Taiwan. Materials and Methods: A total of 88 histologically confirmed breast cancer cases and 344 cancer-free controls were recruited between July 1992 and December 2000. The MTHFR C677T genotype was determined by a PCR-RFLP-based assay. All subjects completed in-person interviews. Results: There was a significant trend of breast cancer in relation to prolonged exposure to estrogens prior to the first full-term pregnancy (FFTP)(p for trend=0.0015). In contrast, there was no statistically significant association between the risk of breast cancer and the MTHFR C677T genotype. However, a significantly elevated risk of breast cancer predisposed by the MTHFR 677T variant genotype (CT and TT) was observed in women with prolonged exposure to estrogens prior to FFTP (adjusted OR=4.98, 95% CI=2.00-12.43).Conclusion: The results of this study suggest that the MTHFR 677T variant genotype per se may have no overall association with breast cancer risk, but a sizable association could be observed in the presence of relevant environmental exposure. Copyright© 2004 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved ER -