Inhibition of cellular tyrosine phosphorylation in BCR-ABL–expressing cells by imatinib and nilotinib, combined. Immunoblot showing inhibitory effects of nilotinib and imatinib (alone and combined) on total cellular tyrosine phosphorylation and BCR-ABL expression in nonmutated BCR-ABL–expressing cells. Immunoblot was hybridized with a beta-actin antibody as a loading control.