Given the context-dependent tumor-suppressive and oncogenic functions of Notch signaling in hematopoiesis (Gu et al., 2016; Kushwah et al., 2014), our results also establish a foundation for exploring analogous Abl/PTP1B-Abi-Notch regulatory mechanisms in mammalian hematopoiesis and leukemia. Here, PTPN1 is linked to leukemia.