In six cases of BPDCN, the positive rate of CD303 was only 50% (3/6), while the expressions of NRP‐1/CD304, CD56, CD4, CD123 and HLA‐DR were all positive, though CD4 was dimly expressed in four BPDCN cases. This evidence concerns the gene NCAM1 and CD4+/CD56+ hematodermic neoplasm.