Because high expression of cereblon (CRBN) and MUM1 have been associated with better response rates in multiple myeloma patients treated with lenalidomide, they investigated CRBN/MUM1 expression assessed by IHC in 46 eMZL (13/46 gastric; 33/46 extragastric) patients treated with lenalidomide-based therapy: 54% showed high expression (CRBN+, ≥ 50% positive cells). The gene discussed is CRBN; the disease is plasma cell myeloma.