Finally, as pCR is rarely achieved by NCT in ER+ breast tumors, we searched if BRCA1 (Pro871Leu), ERCC1 (Asn118Asn), CYP1B1 (Leu432Val) and SLCO1B3 (IVS12-5676) could stand for predictive markers of NCT for patients with this subtype of tumor. The gene discussed is CYP1B1; the disease is neoplasm.