CRBN and plasma cell myeloma: Very recently, two specific B-cell transcription factors, Ikaros family zinc finger-containing protein 1 (IKZF1; Ikaros) and 3 (IKZF3; Aiolos), were found to be the targets of lenalidomide-CRBN ubiquitination degradation in myeloma cells including not only cell lines but also primary myeloma samples [10, 11].