DPH1 and CD4+/CD56+ hematodermic neoplasm: Studies have shown that 5-Aza monotherapy exhibits some clinical efficacy in treating BPDCN, but does not achieve long-term CR.[72,73] Togami et al[74] found that BPDCN resistance to tagraxofusp is associated with downregulation of DPH1, a key regulator of intracellular target delivery of diphtheria toxin, and that 5-Aza can restore DPH1 expression and tagraxofusp sensitivity.