U2AF1 and acute lymphoblastic leukemia: Among these novel putative childhood T-ALL drivers, we identified a number of mutations in chromatin remodeling genes EHMT1 (n = 4), WHSC1 (n = 3) and KMT2C/MLL3 (n = 1), a recurrent missense mutation (p.R35L) in the first zinc finger of splicing factor U2AF1 (n = 3), as well as loss of ABL1 (n = 2) and in MLH1 (n = 2), both involved in DNA repair.