NOTCH1 and acute lymphoblastic leukemia: Dysregulation of the Notch signaling is involved in many hematological and solid malignancies.[5, 25] Notch1 is a well‐characterized oncoprotein in T‐ALL, while Notch1 is believed to be a tumor suppressor in AML.[5, 26] In T‐ALL, there are several reports proposing different molecular mechanisms involved in the leukemogenesis of Notch1.