Overexpression of Runx2 in MM cells promotes tumor progression in vivo. (A) Expression of Runx2 in Runx2 k/in 5TGM1 cells was analyzed by western blot. Runx2 k/in cells show enhanced expression of Runx2 compared with vector control cells. (B) IgG2bκ in serum (marker of total tumor burden) was measured by ELISA at 0, 4, and 6 weeks after IV injection of vector control (blue bar) or Runx2 k/in 5TGM1 cells (red bar) in C57BL/KaLwRij mice (n = 8 per group). Error bars represent mean ± SEM of each group. Significant differences between groups are indicated by P value. (C) Bioluminescent imaging 4 weeks after IV injection of both control and Runx2 k/in 5TGM1 cells (8 mice per group). (i) Robust tumor bioluminescence is observed in mice bearing Runx2 k/in 5TGM1 cells compared with mice bearing control 5TGM1 tumors. (ii) Tumors in mice bearing control 5TGM1cells are detectable by bioluminescence; however, the maximal signal in the control group is 14× less than the Runx2 k/in group as indicated by the different scale bar.