HEN/HESN also encompasses the broad spectrum of other WHO-defined myeloid neoplasms with associated eosinophilia, such as BCR-ABL1+ chronic myeloid leukemia, JAK2-mutated myeloproliferative neoplasms, KIT D816V+ systemic mastocytosis, acute myeloid leukemia (AML) associated with CBFβ fusion gene, myelodysplastic syndromes associated with HE, and other WHO-defined myeloid neoplasms with HE (10). This evidence concerns the gene CBFB and acute myeloid leukemia.