HDAC3 and osteosarcoma: We have recently reported that CBX4 is a tumor suppressor by impairing Runx2 transcription via recruiting HDAC3 to the Runx2 promoter in CRC, while Runx2 plays a crucial role in promoting osteosarcoma metastasis12,13, which was verified by our experiments, as shown in Supplementary Fig. 2.