According to the ICC guidelines, the category of myeloproliferative neoplasms (MPN) include BCR::ABL1-positive chronic myeloid leukemia (CML), essential thrombocythemia (ET), primary myelofibrosis (PMF), and polycythemia vera (PV) as well as chronic neutrophilic leukemia (CNL) and chronic eosinophilic leukemia (CEL). This evidence concerns the gene BCR and chronic neutrophilic leukemia.