TCF4 and acute myeloid leukemia: Aiming to improve the sensitivity of immunophenotyping in the diagnostic of BPDCN, several additional markers have been proposed, e.g., TCF4 and CD304.[45, 49] Particularly, TCF4 is commonly expressed in BPDCN and is negative in other myeloid neoplasms including AML, while CD304 expression was found in all BPDCN cases investigated [45].