Notably, Guglielmelli et al. recently found an association of high mutant CALR VAF (≥55%) with shorter anemia-free and leukocytosis-free survivals, and thereby, more aggressive disease compared to low CALR VAF (<55%) in a cohort of 620 patients who had PMF or secondary MF [75]. Here, CALR is linked to Increased total leukocyte count.