Therefore, we determined the effect of these concentrations of poziotinib on the efficacy of the ABCB1 and ABCG2 transporter anticancer drugs, paclitaxel and doxorubicin and mitoxantrone and SN-38, respectively, in the parental and drug-resistant colon cancer cells and HEK293 cells overexpressing the ABCG2 or ABCB1 transporter. The gene discussed is ABCG2; the disease is colonic neoplasm.