Expression of drug resistance proteins in triple-receptor-negative tumors as the basis of individualized therapy of the breast cancer patients

Chekhun V.F., Zhylchuk V.E., Lukyanova N.Yu., Vorontsova A.L., Kudryavets Yu.I.

Aim: To evaluate the efficacy of the application of various chemotherapy schemes based on the immunohistochemical study of expression patterns of proteins associated with the drug resistance P-glycoprotein (P-gp), glutathione-S-transferase (GST), metallothioneins (МТ) of breast cancer (BC) patients with the triple-receptor-negative (RE–, RP–, HER-2/neu–) cancer. Methods and Results: P-gp, GST and МТ expression in BC-biopsy samples from 60 BC patients was evaluated by immunohistochemical analysis. The results of the clinical observations showed that 3-years relapse-free survival rate of the patients of with P-gp, GST and МТ-positive tumors treated with taxoter + adriablastin / taxoter + cyclophosphamide (ТА/ТС), gemcitabine + carboplatin, or TC + bevacizumab was 61.5%, 78.6% and 81.2% respectively, vs 41.2% in the control group with P-gp, GST and МТ-negative tumors treated with adriablastin + cyclophosphamide (p < 0.05), while overall survival rates were 84.4%, 92.6% and 93.8% respectively vs 70.6% in the control group (p < 0.05). Conclusion: The study points on the possibility to elevate the efficiency of polychemotherapy by its individualization based on the expression patterns of Р-gp, GST and MT on tumor cells of the patients with the triple-receptor-negative BC.