PTPN11 and cancer: For instance, SHP2 dephosphorylatesRasGAP (Ras GTPase) docking sites on EGFR (pTyr992) and on HER2 (pTyr1023)to sustain the activated form of Ras (GTP-Ras).2,15 SHP2has also been shown to dephosphorylate pTyr397 in FAK to facilitatefocal adhesion turnover16 and pTyr314 inPAG to enhance Src Tyr kinase signaling.17 The positive role of SHP2 in tyrosine kinase signaling in generalhas attracted interest to develop specific inhibitors for use in diseases,particularly in cancer, that often involve hyperactive tyrosine kinasesignaling.