A four‐tiered Myelofibrosis Secondary to PV and ET‐Prognostic Model (MYSEC‐PM) was specifically developed for secondary SMF, including older age, hemoglobin < 11 g/dL, circulating blasts ≥ 3%, platelet count < 150 ×109/L, constitutional symptoms, and CALR mutational status as variables [13]. This evidence concerns the gene CALR and myelofibrosis.