Circling back to epigenetic regulation in osteosarcoma: Comment on 'Hsa_circ_0088212-mediated miR-520h/APOA1 axis inhibits the osteosarcoma progression' by ' Hao Peng'.

Osteosarcoma is a genetically complex cancer, thus there are increasing efforts to identify biomarkers and regulators within the epigenome that can better predict patient outcomes and provide new therapeutic targets. In this commentary, we have evaluated the work of Peng and colleagues on the identification and function of the signaling axis circ_0088212/miR_520 h/APOA1 in osteosarcoma. We provide the context of how novel it is to demonstrate the anti-tumor functions of APOA1 and not just correlative gene expression with patient outcome. We further postulate why some studies involving circRNAs in osteosarcoma contradict one another. We conclude that the study performed by Peng and colleagues was performed with enough rigor to give confidence that circ_0088212 is a bona fide tumor suppressor in osteosarcoma.