CDKN3 and CD4+/CD56+ hematodermic neoplasm: Wiesner et al (15) investigated histopathological skin lesion specimens of 14 BPDCN patients and demonstrated that chromosomes 9, 12, 13 and 15 were more likely to be absent, and that the cyclin dependent kinase inhibitor (CDKN) 1B site was most commonly not present (detectable in 64% of the tumors).