IRF4 and plasma cell myeloma: Among the transcription factors altered by cyclin K and/or cyclin D1b expressions, besides MYC, MAF, ETS family members, well-known as major oncogenic actors in plasma cells [13], several others have been implicated in myeloma pathology such as ATF3/4, IRF4/8, NOTCH2, RUNX1/2, XBP1 through the modulation of genes controlling growth, survival and migration.