While inhibiting the metastasis of colon cancer by recruiting histone deacetylase 3 (HDAC3) to the Runx2 promoter [12], CBX4 promotes the metastasis of osteosarcoma by recruiting GCN5, which catalyzes H3K27 acetylation of the Runx2 promoter [13]. Here, HDAC3 is linked to osteosarcoma.