MYC and plasma cell myeloma: Furthermore, the downregulated genes shared among the three myeloma cell lines and treatment with both HDACi contained factors involved in cell cycle regulation, cell proliferation, cell differentiation, and apoptosis of cells such as Myc and Pim-2: the inhibition of which is associated with cell cycle arrest and apoptosis of myeloma cells (refs. 38–40; Fig. 3E and F).