Figure 1.

Immunohistochemical staining of Cereblon and c-Myc in CD138⁺ bone-marrow plasma cells of MM patients. Multiple myeloma BM core biopsies stained with dual CD138 (red membrane) and Cereblon (brown cytoplasm and nucleus) or c-Myc (brown nucleus). Shown are two representative patients at the time of diagnosis (upper panel) and lenalidomide-refractory disease (lower panel). Decreased Cereblon and increased c-Myc expression are noted upon development of lenalidomide resistance. Arrows point to tumor cells. H-scores range from 0 to 600 for Cereblon and from 0–300 for c-Myc. Len: lenalidomide.