Correlation of GST-π and Topo II expression with the chemosensitivity of human breast cancer cells in vitro

Objective: To investigate the correlation of GST-π and Topo II expression with the chemosensitivity of breast cancer cells in vitro. Methods: ATP-tumor chemosensitivity assay (ATP-TCA) was used to determine the effect of 4 single chemotherapeutics [Epirubicin (EPI), Paclitaxel (PTX), Taxotere (TXT), and Gemcitabine (GEM)] and 2 combined regimens [ Epirubicin + Taxotere (EPI + TXT ), Cyclophosphamide + Epirubicin + 5-Fluorouracil (CEF)] of in virro breast cancer cells from 45 breast cancer patients. Expression of GST-π and Topo II was examined by immunohistrochemistry. Results: ATP-TCA showed that the inhibitory rates of EPI, PTX, TXT and GFM for breast cancer cell growth were 62.2 %, 35.6 %, 8.9 %, and 15.6 %, respectively. The inhibitory rates of EPI+TXT and CEF were 77.8 % and 73.3 %, respectively, higher than those of PTX, TXT, and GEM (P < 0.01). Immunohistochemistry showed that the expression rates of GST-π and Topo II were 44.4 % (20/45) and 62.2 % (28/45), respectively. EPI, EPI+TXT and CEF showed higher inhibitory rate in cases with Topo II expression or in cases without GST-π expression (P< 0.01). Conclusion: ATP-TCA combined with detection of GST-π and Topo II expression can be used to screen effective therapeutics against breast cancer.