HMGB1 and osteosarcoma: Overexpression of miR‐505 and silencing of HMGB1 suppressed the proliferation, migration, and invasion of osteosarcoma cells and increased the rate of apoptosis, whereas the co‐transfected miR‐505 mimics + si‐HMGB1 demonstrated a more significant inhibitory effect on the proliferation and invasion of osteosarcoma cells and a higher apoptosis rate.