Results showed that GSTP1 105Val allele (Ile/Val and Val/Val) was associated with a higher breast cancer risk (OR = 1.38, 95% CI: 1.14–1.69; P = 0.001) and more aggressive tumors with histological grade III (OR = 1.15, 95% CI: 1.05–1.26; P = 0.001), lymph node metastases (OR = 2.35, 95% CI: 1.72–3.21; P < 0.001), as well as ER negative (OR = 1.77, 95% CI: 1.31–2.39; P < 0.001) than those carrying the Ile/Ile allele. This evidence concerns the gene GSTP1 and breast cancer.