To understand genetic risk factors that may have a role in pre-menopausal breast cancer we investigated variables of the two cytochrome P450 enzymes (CYP2C8, rs11572080 and CYP3A4, rs2740574) in female cancer breast patients on taxane-based therapy and we evaluated their variation based on menopausal status. This evidence concerns the gene CYP2C8 and breast carcinoma.