Most patients had a mutation in JAK2 (MPN + CML: 80.0%, MPN: 86.5%), followed by mutations in CALR (MPN + CML: 14.5%, MPN: 11.1%) and MPL (MPN + CML: 5.5%, MPN: 3.3%). This evidence concerns the gene JAK2 and chronic myelogenous leukemia, BCR-ABL1 positive.