Osteoclast staining in tibia and spine following hMSC-OPG therapy. Bone tissues were harvested from mice in control and indicated treatment groups 28 days following tumor challenge. The bones were decalcified, and 5-µM sections were made. The slides were stained with TRAP stain on both tibia and spine for osteoclast activity within the bone microenvironment. Original magnification ×100.