Indeed, 10 of the 13 cases (76.9%) discussed here had type 1 or type 1-like CALR mutations and exhibited moderate myelofibrosis, whereas 2 of the other 3 cases harbored type 2 CALR mutation and showed an ET phenotype.[6,13] Altogether, these 13 cases of MPNs more frequently had type 1 and type 1-like CALR mutations in PMF, which led to the evolution of a CALR-mutant MPN to Ph+ CML. The gene discussed is CALR; the disease is myelofibrosis.