We first investigated the cytotoxic potential of TK216 in various pediatric AML and B-ALL cell lines and patient samples, covering frequently observed genetic alterations seen in pediatric patients, like KMT2A rearrangements, FLT3 mutations and gene fusions like ETV6-RUNX1 and BCR-ABL1. This evidence concerns the gene ABL1 and acute lymphoblastic leukemia.