CALR ‐mutated myeloproliferative neoplasms: Refining molecular risk beyond the driver

Abstract

Calreticulin ( CALR )‐mutated myeloproliferative neoplasms (MPNs) are generally associated with favourable outcomes, yet considerable heterogeneity persists across the disease course. Mawalkar et al. provide long‐term data across essential thrombocythaemia (ET), post‐ET myelofibrosis (MF) and primary MF, highlighting the prognostic relevance of additional somatic mutations. The contribution of co‐mutational context, variant allele frequency (VAF), disease origin and timing of molecular assessment remains incompletely defined. Commentary on: Mawalkar et al. Outcome heterogeneity in CALR‐mutated myeloproliferative neoplasms. Br J Haematol 2026 (Online ahead of print). doi: 10.1111/bjh.70859 .