SL1 is a transcription factor that facilitates the transcription of rRNA by recruiting RNA Pol I.40 Myc recruits RNA Pol I to target promoters by interacting with the TBP-associated factor, a component of the SL1 complex.41 CX-5461, a small molecule inhibitor of RNA Pol I, represses the proliferation of neuroblastoma cells42 and myeloma by inhibiting Myc expression and activating p53, leading to cancer cell apoptosis.43 Therefore, targeting ribosome biogenesis provides a new opportunity to treat tumors expressing high levels of Myc. This evidence concerns the gene MYC and plasma cell myeloma.