ABCB 1 polymorphism as prognostic factor in breast cancer patients treated with docetaxel and doxorubicin neoadjuvant chemotherapy

Expression of the adenosine triphosphate‐binding cassette B1 ( ABCB 1 ) transporter and P‐glycoprotein are associated with resistance to anticancer drugs. The purpose of this study was to investigate the role of single nucleotide polymorphism in the ABCB 1 and CYP 3A genes in breast cancer patients who were treated with neoadjuvant chemotherapy. Stage II / III breast cancer patients were treated with three cycles of neoadjuvant, after which the patients received curative surgery and adjuvant chemotherapy. The polymorphisms of ABCB 1 and CYP 3A were genotyped. The correlation of polymorphism of ABCB 1 , CYP 3A, and clinical outcomes was analyzed. Among the 216 patients, ABCB 1 3435 TT genotype had a longer overall survival (OS). than CC/CT. Multivariate analyses demonstrated that good PS , invasive ductal carcinoma, non‐triple negative phenotype and initial operable stage were significantly associated with a lower death risk. ABCB 1 3435 TT genotype had a higher AUC than CC / CT for docetaxel. These higher AUC s in the C3435 TT was associated with increased toxicities of neutropenia and diarrhea. This study showed that the genetic polymorphism of ABCB 1 C3435T might be associated with a longer OS . Our results also suggest that the prediction of docetaxel toxicity might be possible for C3435T polymorphism. This study results provides valuable information on individualized therapy according to genotypes.