As observed in screens for lenalidomide resistance in multiple myeloma, CC-885 requires the components of the CRL4CRBN ubiquitin ligase, genes required for neddylation of cullin-RING ligases, and the UBE2G1 E2 ubiquitin–conjugating enzyme (29) (Figure 3, A and B, and Supplemental Figure 3A). This evidence concerns the gene UBE2G1 and plasma cell myeloma.