The carriers of variant TT genotype of SNP rs2278749 in the BMAL1 gene with an OR of 0.45 (95% CI, 0.23- 0.90) and the homozygote genotype TT of rs3749474 in the CLOCK gene with an OR of 0.64 (95% CI, 0.45- 0.92) had reduced risk of breast cancer. Here, CLOCK is linked to breast cancer.