Survival data on 440 patients with PMF stratified by their JAK2 and CALR mutational status. Patients with CALR mutations were further substratified into type 1/type 1-like and type 2/type 2-like, based on the helical propensity of their mutant CALR C terminus. Among these 440 patients, 264 (60%) deaths (205 JAK2, 45 type 1/type 1-like and 14 type 2/type 2-like CALR mutated) and 40 BTs (27 JAK2, 10 type 1/type 1-like and 3 type 2/type 2-like CALR-mutated) were documented.