ABCB1 and leukemia: The observations made here with nilotinib-vincristine combinations in leukemia cells are in line with previously reported synergistic in vitro effects of nilotinib and vincristine in certain ABCB1- or ABCC10-overexpressing tumors (81–83), and with the absence of antagonism in several other preclinical tumor models, including oral squamous cell carcinoma (84, 85).