IRF4 and plasma cell myeloma: Utx/BrafV600E plasma cells before and after overt MM showed gradual up-regulation and down-regulation of DEGs (Fig. 6C upper panel), including representative myeloma signature genes with upregulation of Myc, Ccnd2, E2f3, and Irf4 and downregulation of Cd19 and Ikzf3 (Fig. 6C lower panel, D).