Correlation between chemotherapy response and expression profiles of transmembrane proteins: P-glycoprotein (ABCB1), MRP2 (ABCC2), BCRP (ABCG2) in patients with invasive breast cancer

Overexpression of ABC drug transporters can cause multidrug resistance (MDR) in cancer cells, which is a major obstacle in the success of cancer chemotherapy. Our study revealed a correlation between the expression of invasive breast cancer resistance-associated proteins, such as P-glycoprotein (ABCB1), MRP2 (ABCC2), BCRP (ABCG2) in tumor cells and pathologic response to neoadjuvant chemotherapy. The response to neoadjuvant chemotherapy was shown to be associated with a lack of BCRP expression in tumor cells. The pathologic tumor response was correlated with the presence of positive MRP2 expression and the expression level of P-glycoprotein in cells of invasive breast cancer.