PTPN11 and cancer: Indeed, the SHP2-encoding gene, protein tyrosine phosphatase non-receptor type 11 (PTPN11), has been defined as a bona fide proto-oncogene and is involved in tumorigenesis, being overexpressed in various cancers or relaying proliferation signals from upstream oncogenes, such as Epidermal Growth Factor Receptor (EGFR), KIT, or Fms-like tyrosine kinase 3 (FLT3) mutants.