CDKN1B and CD4+/CD56+ hematodermic neoplasm: Common chromosomal deletions have been identified in previous studies, mainly at 5q21 or 5q34, 12p13, 13q13-q21, 6q23-qTER, 15q, and throughout chromosome 9.[25] Notably, duplicated chromosomal deletions in BPDCN often result in gene loss at related loci, mainly including oncogenic factors (TP53, PTEN, NR3C1), cell cycle regulators (CDKN1B, CDKN2A/CDKN2B), and transcription factors (ETV6, IKZF1).[26–29] Among them, 9p21.3 (CDKN2A/CDKN2B) deletion, which is associated with poor prognosis, and 12p/ETV6 deletion, which may represent early clonal events, are common in BPDCN.[27,28]