The Effect of CYP2C19*2 (rs4244285) and CYP17 (rs743572) SNPs on Adriamycin and Paclitaxel based Chemotherapy Outcomes in Breast Cancer Patients.

Background: Cytochrome P450 (CYP) are phase I metabolizing enzymes involved in detoxification of chemotherapeutic agents. Among the CYP gene family, including CYP1A1, CYP1B1, CYP2C, CYP2D, CYP2E and CYP17, their significance in cancer susceptibility is well established. However, there remains limited understanding regarding the polymorphisms of CYP2C19*2 and CYP17 and their potential correlation with chemotherapy-induced toxicity reactions in breast cancer (BC) patients. In this study we intended to identify the association of CYP2C19*2 and CYP17 gene polymorphisms on drug response as well as toxicity reactions in BC patients undergoing adriamycin/paclitaxel based chemotherapy within Indian population.

Methods: Two hundred BC patients receiving adriamycin and paclitaxel chemotherapy were enrolled in this study and chemotherapy induced hematological and non-hematological toxicity reactions were noted. The polymorphisms of CYP2C19*2 (681G>A) and CYP17 (34T>C) isoforms of cytochrome p 450 gene was studied by PCR and RFLP analysis.

Results: The univariate logistic regression analysis revealed significant associations between CYP2C19*2 (681 G>A) polymorphisms with hematological toxicities i.e., anemia (OR=9.77, 95% CI: 2.84-33.52; p=0.0003), neutropenia (OR=5.72, 95% CI: 1.75-18.68; p=0.003), febrile neutropenia (OR=4.29, 95% CI: 1.32-13.87; p=0.014) and thrombocytopenia (OR=5.86, 95% CI: 1.15-29.72); p=0.032) in BC patients. Additionally BC patients treated with adriamycin exhibited significant association between CYP2C19*2 polymorphism with chemotherapy induced nausea and vomiting (CINV) (OR=99.73, 95% CI: 5.70-174.64); p=0.001), fatigue (OR=83.29, 95% CI: 4.77-145.69); p=0.002), bodyache (OR=4.44, 95% CI: 1.24-15.91); p=0.021) and peripheral neuropathy (OR=12.00, 95% CI: 1.80-79.89); p=0.010. Furthermore, the regression analysis indicated an association between CYP17 with body ache (OR=2.77, 95% CI: 1.21-6.34; p=0.015) and peripheral neuropathy (OR=3.90, 95% CI: 1.59-9.53; p=0.002) in BC patients treated with paclitaxel chemotherapy.

Conclusion: The findings obtained from this study illustrated significant association of CYP2C9*2 (681G>A) polymorphism with adreamicin based chemotherapy induced toxicities and CYP17 (34T>C) polymorphism with paclitaxel induced bodyache and peripheral neuropathy in BC patients.