CD123 is highly expressed on several hematologic neoplasms, including AML, acute lymphoblastic leukemia (ALL), blastic plasmacytoid dendritic cell neoplasm (BPDCN), hairy cell leukemia and certain lymphomas, but expressed at a low level or to be absent on normal hematopoietic stem cells. This evidence concerns the gene IL3RA and acute lymphoblastic leukemia.