Thrombosis is a major risk factor for early mortality in patients with myeloproliferative neoplasms (MPNs), particularly essential thrombocythemia and polycythemia vera. In this insightful interview, Martin Ellis, MD, of Tel Aviv University, Tel Aviv, Israel, details studies that have identified the JAK2 V617F mutation as a key driver of thrombosis, which could then be incorporated into traditional patient risk stratifications for more accurate prognoses. Dr Ellis highlights important areas for further study, such as targeting hematocrit levels, and the need to establish an effective secondary prophylaxis protocol for MPN patients who have previously experienced thrombotic events. This video was recorded at the Myeloproliferative Neoplasms Advances Day 2017, London, UK.