PV has a 98 % frequency of JAK2 mutation, while ET has a 50–60 % frequency of JAK2 mutation, 22 % frequency of calreticulin (CALR) mutation, and 3 % frequency of thrombopoietin receptor myeloproliferative leukemia virus (MPL) mutation. The gene discussed is CALR; the disease is acquired polycythemia vera.