PTPN11 and acute lymphoblastic leukemia: NGS studies have identified oncogenic gain-of-function mutations in the KRAS, NRAS, PTPN11, BRAF, FLT3, CBL, and CBLB genes as well as loss of function mutations in the NF1 gene, which is a negative regulator of the RAS pathway in patients with ALL [24,42,43].