JAK2 V617F mutations can drive a spectrum of disease across the PV, ET or PMF phenotypes through activation of erythropoietin receptor (EPOR), thrombopoietin receptor (MPL) and granulocyte-colony stimulating factor receptor (G-CSFR) receptors present on differing stages of a maturing myeloid cell. The gene discussed is CSF3R; the disease is acquired polycythemia vera.