MYC and plasma cell myeloma: Regarding these genes in which the expression levels are altered by HDACIs, upregulation of the surface TRAIL death receptors (DR4 and DR5) in multiple myeloma (19), upregulation of p21 and p27 in mantle cell lymphoma (20), and downregulation of c-Myc in AML and endometrial cancer cells (13,21) played a key role in the induction of apoptosis and cell cycle arrest or the promotion of cellular differentiation.