In colon carcinoma cells and osteosarcoma cells, MEG3 recruited polycomb repressive complex 2 (PRC2), a chromatin-modifying enzyme, which catalyzes the methylation of histone H3 at lysine 27 (H3K27me1/2/3) on the MDM2 promoter, causing MDM2 downregulation and p53 activation [46]. The gene discussed is MDM2; the disease is osteosarcoma.