It was worth noting that CALR mutations were detected in three patients, in which, two (MDS-f and MDS-LB subtype, respectively) were type I mutations,19 and the other one (MDS-f) was type II mutation.19 All three patients were transformed from primary myelofibrosis with ≥grade 2 myelofibrosis. The gene discussed is CALR; the disease is primary myelofibrosis.