ACVR2A and osteosarcoma: The data presented here extend these findings and show that ActRIIA‐mFc or FSTΔHBS‐hFc therapy may also blunt osteosarcoma primary tumor volume, possibly as a consequence of modulated tumor‐associated bone remodeling: Both ActRIIA‐mFc and FSTΔHBS‐hFc were capable of abolishing activin A's enhancement of osteoclastogenesis.