ABCB1 and cancer: Besides the BGJ 398-induced impairment of ABCB1 function shown here, we recently demonstrated an ability of this RTKi to sensitize cancer cells to topoisomerase II inhibitors (e.g., doxorubicin) via attenuation of homology-mediated DNA repair [109], thereby illustrating the complex mechanism of BGJ 398-induced sensitization of cancer cells to the chemotherapeutic agents.