In conclusion, the results of this in vitro study indicate that sapitinib completely reverses the resistance of SW620/Ad300 and HEK293/ABCB1 cells overexpressing ABCB1 transporter to the anti-cancer drugs, paclitaxel and doxorubicin, which are ABCB1 substrates. The gene discussed is ABCB1; the disease is cancer.