Multidrug transporters P-GP, MRP1, and ABCG2 in chemoresistant breast and colorectal cancer cells—who takes the lead?

Despite significant advances in the discovery and efficacy of anticancer drugs, chemoresistance remains a major issue in cancer treatment and management. Hyperactivity of efflux pumps is one of the key mechanisms through which cancer cells acquire chemoresistance. This study investigates the expression patterns of P-GP, MRP1, and ABCG2 in 49 paired chemoresistant breast and colorectal cancer tissues using immunofluorescence imaging and statistical applications. Among breast cancer patients, 92.86% were diagnosed with infiltrating ductal carcinoma, whereas in the case of colorectal cancer, 100% had adenocarcinoma. Our immunofluorescence data show concurrent expression of ABCG2, MRP1, and P-GP across all chemoresistant breast and colorectal cases, suggesting a synergistic action of these transporters in developing chemoresistance, although the expression level varied for the transporters. Expression of ABCG2 exceeded P-GP and MRP1 expression in most cases. We suggest that a combinative and targeted therapeutic approach may be beneficial to improve the prognosis of cases with chemoresistance.