RT Journal Article
SR Electronic
T1 Sunlight, Polymorphisms of Vitamin D-related Genes and Risk of Breast Cancer
JF Anticancer Research
JO Anticancer Res
FD International Institute of Anticancer Research
SP 543
OP 551
VO 33
IS 2
A1 BARBARA J. FUHRMAN
A1 D. MICHAL FREEDMAN
A1 PARVEEN BHATTI
A1 MICHELE M. DOODY
A1 YI-PING FU
A1 SHIH-CHEN CHANG
A1 MARTHA S. LINET
A1 ALICE J. SIGURDSON
YR 2013
UL http://ar.iiarjournals.org/content/33/2/543.abstract
AB Background/Aim: Geographic gradients in breast cancer incidence and mortality suggest that vitamin D may reduce risk. The enzyme 25-hydroxyvitamin D 24-hydroxylase (CYP24A1), which degrades the active form of vitamin D, and the vitamin D receptor (VDR) are both found in breast tissue. We investigated six polymorphisms in CYP24A1 and two in the VDR gene in association with breast cancer risk. Materials and Methods: We conducted a case–control study within the nationwide U.S. Radiologic Technologists cohort, including 845 controls and 484 incident breast cancer cases. Associations of polymorphic variants and ecologic and personal measures of sun exposure with breast cancer risk were assessed using unconditional logistic regression. Results: Two polymorphisms in CYP24A1 were associated with increased breast cancer risk (rs34043203, Ptrend=0.03; rs2762934, Ptrend=0.005) and one with reduced breast cancer risk (rs1570669, Ptrend=0.048). Risk was inversely associated with minor alleles for the VDR Bsm1 polymorphism (rs1544410, Ptrend=0.05) but not Fok1 (rs2228570). Sunlight measures were not associated with breast cancer risk, however significant interactions between time outdoors in the teen years and three unlinked genotypes were found for VDR (rs1544410, rs2228570) and CYP24A1 (rs1570669). Conclusion: In this nation-wide breast cancer case–control study, we found that the vitamin D pathway was involved in disease etiology and our results further suggest that reduced cancer risk, in association with sunlight, may depend on timing of exposure and genetic background. These findings merit further investigation.