In a total of 617 patients with PMF from four centers, the cumulative incidence of developing anemia in CALR-mutated patients was lower compared to JAK2-mutated (p < 0.001), MPL-mutated (p = 0.004), and “triple-negative” (p < 0.001) patients; the likelihood that “triple-negative” patients would develop anemia was higher than in CALR-mutated (p < 0.001) or JAK2-mutated (p = 0.013) patients [52]. This evidence concerns the gene JAK2 and anemia (phenotype).