NOTCH1 and acute lymphoblastic leukemia: Then, ICN1 translocates into the nucleus and activates NOTCH1 target genes, such as c-Myc, Hes1, and Dtx1. 2–5 Activating mutations in NOTCH1 that induce ligand-independent activation of the receptor or an increase in the stability of ICN1 are found in more than 60% of human T-cell acute lymphoblastic leukemia (T-ALL) cases.