CALR and myeloproliferative neoplasm: Most patients with MPN had the JAK2V617F-mutation (MPNd, 91%; MPNn 82%)), and fewer had mutations in the calreticulin (CALR) gene (MPNd, 3%; MPNn 11%) and the thrombopoietin receptor (MPL) gene (MPNd 3%; MPNn 0%).