ABL1 and acute lymphoblastic leukemia: For example, PTPN1 were inactivated in acute lymphoblastic leukemia SupB15 cells with resistance of ABL kinase inhibitor STI571, and accompanied by phosphorylating Bcr‐Abl, and exogenous inhibition of PTPN1 could attenuate STI571‐induced apoptosis, and enhance the resistance to STI571, which suggested that PTPN1 may be closely related to the sensitivity of targeted drugs.