Viability of the 2 cell lines harboring the ABL1 fusion genes was clearly impaired by imatinib, and differed significantly each other (p < 0.0001) with the ALL-SIL being more sensitive (IC50 = 46.9 ± 6.99 nM) than K562 [0.38 ± 0.13 μM in accordance to previously reported values (Quintás-Cardama and Cortes, 2009)]. The gene discussed is ABL1; the disease is acute lymphoblastic leukemia.