Eleven ALL cell lines (Nalm6, SEM, 697, UOCB-1, REH, JIH5, RPMI8402, CEM, Jurkat, DND41, and MOLT4) representing DUX4, KMT2A-r, TCF3-PBX1, TCF3-HLF, ETV6-RUNX1, ZNF384-r, and T-ALL subtypes were subjected to drug-sensitivity assay in vitro, using FLT3 inhibitor gilteritinib. The gene discussed is TCF3; the disease is acute lymphoblastic leukemia.