ABCB1 and cancer: In summary, without excluding the possibility that other mechanisms may also contribute to the reversal of multidrug resistance and that adverse drug reactions have been reported in combination therapy [69,70,71], our study demonstrated that erdafitinib is an FDA-approved therapeutic agent that could be utilized to fight multidrug-resistant cancers associated with the overexpression of ABCB1, and the concomitant administration of cytotoxic anticancer drugs with erdafitinib warrants further investigation.