JAK2 and Splenomegaly: Interestingly, in PMF, a recent meta-analysis found that CALR-mutated patients displayed a lower risk of splenomegaly (OR 0.47, 95% CI 0.29–0.78) and thrombosis (OR 0.52, 95% CI 0.29–0.92) when compared with JAK2-mutated patients [19].