Other mutated genes in T-ALL are WT1, NRAS, the negative regulator of the RAS pathway, NF1 that is inactivated because of deletions or mutations [80], and rarely FLT3 [81, 82] and PTPN2 [83], that are affected by activating mutations and focal deletions, respectively. The gene discussed is FLT3; the disease is acute lymphoblastic leukemia.