CYP2E1 and breast cancer: For the CYP2E1*5 Rsa I/Pst I (c1/c2) polymorphism, we still failed to identify any significant association with BC susceptibility: (1) c2 vs. c1 (OR = 0.97, 95% CI = 0.80–1.17, P = 0.718); (2) c2/c2 vs. c1/c1 (OR = 0.74, 95% CI = 0.42–1.30, P = 0.300); (3) c1/c2 vs. c1/c1 (OR = 1.03, 95% CI = 0.81–1.29, P = 0.797); (4) c2/c2 + c1/c2 vs. c1/c1 (OR = 1.00, 95% CI = 0.80–1.24, P = 0.994); (5) c2/c2 vs. c1/c2 + c1/c1 (OR = 0.75, 95% CI = 0.43–1.30, P = 0.303) (Fig. 2b).