Runx2/Cbfa1 immunostaining in BM biopsies of patients with MM. (A) Histomorphometry and Runx2/Cbfa1 immunostaining performed on BM biopsies of 40 patients with MM who either had bone lesions or did not have skeletal involvement as described in “Patients, materials, and methods.” Graphs and bars represent the mean ± SD of the number of osteoblasts (OBs)/mm2, the number of total Runx2/Cbfa1 positive stromal/osteoblastic cells, and the % of Runx2/Cbfa1-positive OBs. (B) Runx2/Cbfa1 immunostaining performed in a trabecula of 2 representative patients with MM who did or did not have bone lesions (original magnification, × 1000). See “Immunohistochemistry” for image acquisition details.