SFPQ-ABL1 transforms IL-7–dependent Pu.1/Irf4 DKO cells, and these cells are sensitive to TKIs that target ABL1. (A) western blot analysis of Abl and P-CrkL (Y207) expression in 3 biologically independent Pu.1/Irf4 DKO cell lines expressing BCR-ABL1 or SFPQ-ABL1. (B) Viability analysis after 48- and 96-hour IL-7 withdrawal in Pu.1/Irf4 DKO cells expressing BCR-ABL1 (blue) or SFPQ-ABL1 (red). Viability was determined by propidium iodide (PI) exclusion, measured by flow cytometry. Groups were compared by using unpaired Student t tests with Holm-Šídák correction for multiple comparisons (error bars show mean ± standard error of the mean, n = 6). *P < .05, **P < .01, ****P < .0001. (C) Viability analysis of Pu.1/Irf4 DKO cells expressing MSCV, BCR-ABL1, or SFPQ-ABL1 treated with a dose titration of imatinib, dasatinib, ponatinib, or ruxolitinib. Data are normalized to vehicle control (0.001% dimethyl sulfoxide [DMSO]; not shown on graphs), and nonlinear regression analysis was performed to fit dose–response curves. Data are presented as mean ± standard error of the mean (n = 3).