JAK2 and Venous thrombosis: In another cohort of Italian patients [101], the risk of developing thrombosis was 2.5-fold higher in patients with ET (7.1% vs. 2.8%; p = 0.059), and 3.7-fold higher in patients with PV (10.5% vs. 2.8%; p = 0.001) with JAK2 mutations compared with CALR mutation.