JAK2 and Venous thrombosis: Univariate analysis for venous thrombosis-free survival (V-TFS) identified the presence of JAK2 mutation (p = 0.01) and previous venous event (p = 0.04) as predictors of a subsequent venous thrombosis; conversely, cytoreductive therapy displayed a protective role on venous thrombosis during follow-up (p = 0.006), whereas aspirin had a borderline significance (p = 0.09).