BCR and leukemia: To dissect the molecular mechanisms of acquired resistance to inhibitors of TK pathway, we generated drug-resistant derivatives of leukemia cells K562 (BCR::ABL1 ), MV4–11 (FLT3) and Kasumi-1 (c-KIT) by long-term culture in the presence of TKIs nilotinib (second generation) or imatinib (first generation) (10, 30, 100, 300, 1,000 nM).