NOTCH1 and acute lymphoblastic leukemia: Other tumor-associated aberrant signaling pathways that frequently occur in human T-ALL arise from activating mutations in genes such as NOTCH1 (>60%), IL-7R, JAK/STAT, K–RAS and N–RAS, and inactivating mutations in PTEN and CDKN2A/2B (>70%) [22,23,24].