PTPN11 and B-cell acute lymphoblastic leukemia: Mutations in the PTPN11 gene that lead to SHP-2 hyper-activation have been identified in Noonan syndrome, juvenile myelomonocytic leukemia, myelodysplastic syndrome, B-cell acute lymphoblastic leukemia, acute myeloid leukemia, and several solid tumors (107–109).