Calreticulin Mutation Is Associated with Milder Disease in Patients with Post Essential Thrombocythemia Myelofibrosis (PET-MF) Compared with JAK2V617F Mutation: A Study from the AGIMM Group

Mutations in the gene calreticulin (CALR) were recently discovered in 60-80% of patients (pts) with primary myelofibrosis (PMF) and essential thrombocythemia (ET) who were un-mutated for JAK2V617F and MPLW515. CALR mutated PMF pts had better overall survival (OS) compared with JAK2V617F or MPLW515 mutated while in ET CALR mutations were associated with lower incidence of thrombosis although the effect on survival was not significant. Conversely, there is no information concerning the impact of CALRmutation on disease phenotype and prognosis in post-essential thrombocythemia myelofibrosis (PET-MF).