CRBN and plasma cell myeloma: The nuclear localisation of CRBN is required for regulating Ikaros transcriptional activity in response to thalidomide48 and more recently, a genome-wide screen for factors affecting the anti-myeloma activity of pomalidomide identified Karopherin beta 1 (KPNB1), a nuclear import protein required for nuclear import of CRBN and CRBN-dependent degradation of IKZF346.