%0 Journal Article %A WEI-YU LIN %A YU-CHING CHOU %A MEI-HSUAN WU %A HAN-BIN HUANG %A YI-LIN JENG %A CHO-CHIEH WU %A CHENG-PUNG YU %A JYH-CHERNG YU %A SAN-LIN YOU %A TANG-YUAN CHU %A CHIEN-JEN CHEN %A CHIEN-AN SUN %T The MTHFR C677T Polymorphism, Estrogen Exposure and Breast Cancer Risk: A Nested Case-control Study in Taiwan %D 2004 %J Anticancer Research %P 3863-3868 %V 24 %N 6 %X 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 %U https://ar.iiarjournals.org/content/anticanres/24/6/3863.full.pdf