The study included 192 (37%) patients with PV (median age 45 years; 53% females) and 178 (34%) with ET (median age 39 years; 71% females; 85% JAK2 mutated) and affected veins included portal (67%), hepatic (25%), splenic (29%), and mesenteric (24%) [151]. This evidence concerns the gene JAK2 and acquired polycythemia vera.