In subjects with at least four consecutive night shifts, increased risk of breast cancer was associated with variant alleles of BMAL1 (rs2290035 (OR 1.91, 95% CI 1.08- 3.37; and OR 1.95, 95% CI 0.97- 3.90) and rs969485 (OR 1.64, 95% CI 1.03- 2.61; and OR 1.63, 95% CI 0.96- 2.76)) and ROR-b (rs3750420 (OR 1.60, 95% CI 1.0- 2.56), rs3903529 (OR 2.77, 95% CI 0.98- 7.86)) and MTNR1B rs10830963 (OR 9.12, 95% CI 1.14- 73.09). Here, MTNR1B is linked to breast carcinoma.