ZFX and neoplasm: Conclusions: These results strongly suggest that ZFX is a novel proliferation regulator that promotes growth of Osteosarcoma cells, and downregulation of ZFX expression induces growth suppression of Saos-2 cells via arrested G0/G1 phase cell cycle and apoptosis pathways, thereby indicating that ZFX may serve as a new molecular target for Osteosarcoma tumor therapy.