In this study, patients were followed up (median for 64 months, range 1–214 months) for both detection of JAK2 p.V617F and diagnosis of MPN: 9 of 13 patients with the initial finding of JAK2 p.V617F and 6 of 8 patients with detection of JAK2 p.V617F during follow-up were diagnosed with MPN during the course of the study. This evidence concerns the gene JAK2 and myeloproliferative neoplasm.