Expression of SHH in BM biopsy samples from MM patients and healthy donors. (A) Immunohistochemistry staining for SHH in BM samples of (a) 1 of 4 healthy donors or (b,c,e,f,g) 1 of 5 MM patients. Higher magnifications—in (d), they were derived from the (c) field (black arrow) or in (h), they were derived from the (g) field (black arrow)—show that SHH staining was observed only in MM plasma cells but not in non–plasma cells or BM hematopoietic cells. (B) Percentages of SHH-positive cells in normal BM (nBM cells) from 4 healthy donors and SHH-positive MM plasma cells (Pt BM PC) or MM non–plasma cells (Pt BM non-PC) from 8 MM patients (Pts). (C) Morphology and staining for CD90, CD166, and SHH in cultured MSCs (upper panels), MM patients’ BM samples (Pt BM; middle panels), and normal BM samples from healthy donors (lower panels). Only very few CD90⁺ or CD166⁺ MSCs or SHH-expressing cells (indicated by red arrows) could be detected in patient BM or normal BM. Ctrl, control.