The arterial thrombosis rate before and at the time of diagnosis was lower in the CALR-mutation patients than in the JAK2 V617F-positive patients, and the total venous thrombosis rate in patients aged <60 years at the time of diagnosis was lower in the CALR-mutation and triple-negative patients than in the JAK2 V617F-positive patients. Here, JAK2 is linked to Venous thrombosis.