RESUMEN
BACKGROUND: Osteosarcoma is the most common primary malignant bone tumor, mainly affecting children, young adults, and the elderly. It is an aggressive cancer with a poor prognosis, exhibiting low survival rates even with standard treatment. Recently, circular RNA molecules capable of influencing gene expression through various functions, with their main role being acting as microRNA sponges and reducing their intracellular expression, have been identified. Recent studies have linked circular RNAs to osteosarcoma development and progression. Therefore, the present study aimed to investigate the alteration in circular RNA expression during osteosarcoma development and progression. METHODS: An integrative literature review was conducted from September 10th to November 12th, 2021, using the following databases: PubMed/MEDLINE, SCOPUS, Web of Science, OVID, and EMBASE. 129 full articles were included in the review. The obtained data were organized using a standardized data collection instrument, which included the following information: altered expression profile of circular RNAs, associated cancer hallmarks, clinical-pathological relationships of circular RNAs, and perspectives on the studied circular RNAs. RESULTS: A total of 94 distinct circular RNAs were identified, predominantly showing an increased expression pattern. Approximately 91% of the studies that aimed to identify the mechanisms of action of circular RNAs highlighted the function of circular RNAs as microRNA sponges. The most associated cancer hallmarks with the identified circular RNAs were proliferative signaling induction, invasion and metastasis, and resistance to cell death. The altered expression of these circular RNAs generally correlated with a worse prognosis for patients, as evidenced by clinical features such as shorter survival, advanced Enneking and/or TNM stage, higher incidence of metastasis, larger tumor size, and increased chemoresistance. CONSLUSION: These findings indicate the significance of circular RNA molecules in osteosarcoma carcinogenesis, suggesting their potential as new prognostic and/or diagnostic biomarkers, as well as alternative therapeutic targets in the fight against osteosarcoma.