GSTP1 and breast cancer: Significantly reduced BC risk was related to GSTT1 null and SOD2 Ala16Val + Val16Val genotype (OR 0.55, 95 % CI 0.32–0.96; P = 0.04) and GSTP1 Ile105Val + Val105Val and GSTT1 null and SOD2 Ala16Val + Val16Val genotype (OR 0.22, 95 % CI 0.09–0.56; P = 0.001).