Runx2 expression in plasma cells of normal bone marrow donors, MGUS, and MM patients. (A) Runx2 staining of plasma cells in normal bone marrow, MGUS, and MM patient biopsies. Strong Runx2 expression (brown color) was seen in the nuclei and cytoplasm of MM cells, whereas light staining was found in plasma cells of normal bone marrow donors and MGUS patients as indicated by arrows (original magnification, ×400). Not all positively stained cells are shown. (B) Runx2 staining density in cytoplasm and nuclei of plasma cells in normal (blue bars), MGUS (red bars), and MM patient (green bars) groups. Error bars represent mean ± SEM. Significant differences between groups are indicated by P value. (C) Runx2 mRNA expression was measured by gene microarray and compared between normal (NPC), MGUS, and MM patient groups. The number of patients in each group (n) is shown. (D) Runx2 expression was compared between low-risk and high-risk MM patients by gene expression profiling (GEP). The number of patients in each group (n) is shown. Significant differences between groups are indicated by P value.