By using Next Generation Sequencing techniques, we and others identified recurrent missense somatic mutations occurring on ETNK1 in about 13% of patients affected by atypical chronic myeloid leukemia (aCML)6, in 3–14% of chronic myelomonocytic leukemia (CMML)6,7, and in 20% of systemic mastocytosis (SM) patients with eosinophilia7. Here, ETNK1 is linked to systemic mastocytosis.