CD123 (IL-3Rα) is normally expressed on a fraction of myeloid progenitors and a wide range of hematologic malignancies, including blastic plasmacytoid dendritic cell neoplasm (BPDCN), hairy cell leukemia, B-ALL, MDS, and AML [116, 117, 144]. This evidence concerns the gene IL3RA and hairy cell leukemia.