To understand the mechanisms of the resistance of MPN cells to TGF‐β we undertook a gene expression analysis in JAK2‐mutated cells and identified for the first time a reduced expression of the PTPN6 gene, coding for the SH2 domain‐containing phosphatase 1 (SHP‐1), in JAK2V617F cells. The gene discussed is JAK2; the disease is myeloproliferative neoplasm.