Screening for MPN Mutations in Cases of Deep Vein Thrombosis and/or Pulmonary Embolism: What We have learnt from Studies

Myeloproliferative neoplasms (MPN) are chronic myeloid disorders characterized by a high-risk of thrombosis. One-third is in venous vessels. Clinicians who treat patients experiencing thromboses in such vessels know the high rate of cancer in such situation. Many studies have been published concerning the screening for mutations that drive MPNs (mostly JAK2V617F and CALR mutations) in case of deep vein thromboses and/or pulmonary embolism. We reviewed the results of the studies published since 2005 (year of discovery of JAK2V617F, the most frequent of these mutations) and we analyzed the prevalence of mutations among the patients and their characteristics. Sixteen studies have been published on this topic. Of 2907 patients, 39 (1.3%) were positive for JAK2V617F, reaching 2.1% in case of history of recurrence. CALR mutations have not been found in any of the studied situations. Women represent 73.5% of the cases. Patients over the age of 60 account for 76.5% of the cases. Only 10 (29.4%) of the patients have been identified to have MPN despite a median follow-up period of 42 months. All had thrombocytosis or polycythemia at the time of the thrombosis. Nineteen patients experienced thrombotic recurrence, describing JAK2V617F mutation as a pro-thrombotic factor. Screening for JAK2V617F or CALR mutations should not be systematically performed for patients experiencing deep vein thromboses and/or pulmonary embolism because of the low rate of positivity. Attention should perhaps be focused on patients with persistent thrombocytosis or polycythemia who have a higher rate of MPNs. For the other positive cases with no features of MPN, the management is unclear, but a thorough evaluation by a hematologist should be performed, and the patients should be followed for years.