Further experimental evidence comes from another murine study reporting that a mutated form of protein tyrosine phosphatase SHP2 (encoded by PTPN11), a positive regulator of the RAS signalling pathway, in MSCs and osteoprogenitors, drives the development and progression of myeloproliferative neoplasms (MPN) through severe detrimental effects particularly on HSCs. The gene discussed is PTPN11; the disease is myeloproliferative neoplasm.