Vitamin D-associated genetic variation and risk of breast cancer in the breast and prostate cancer cohort consortium (BPC3).

Background: Two recent genome-wide association studies (GWAS) identified SNPs in or near four genes related to circulating 25-hydroxyvitamin D [25(OH)D] concentration. To examine the hypothesized inverse relationship between vitamin D status and breast cancer, we studied the associations between SNPs in these genes and breast cancer risk in a large pooled study of 9,456 cases and 10,816 controls from six cohorts.
Methods: SNP markers localized to each of four genes (GC, CYP24A1, CYP2R1, and DHCR7) previously associated with 25(OH)D were genotyped and examined both individually and as a 4-SNP polygenic score. Logistic regression was used to estimate the associations between the genetic variants and risk of breast cancer.
Results: We found no association between any of the four SNPs or their polygenic score and breast cancer risk.
Conclusions: Our findings do not support an association between vitamin D status, as reflected by 25(OH)D-related genotypes, and breast cancer risk.
Impact: These findings may contribute to future meta-analyses and scientific review articles, and provide new data about the association between vitamin D-related genes and breast cancer. Cancer Epidemiol Biomarkers Prev; 24(3); 627-30. ©2014 AACR.
(©2014 American Association for Cancer Research.)