骨肉瘤是最常见的原发性恶性骨肿瘤，全球儿童和青少年中居第三位的癌症，仍然是一个重大的治疗挑战。尽管联合化疗和手术切除使生存率提高到60％，但大多数恶性骨肉瘤转移患者的预后仍然不容乐观。肿瘤侵袭和转移的特定发病机制和关键调控因子仍然尚未完全解析。环状RNA(circRNAs)是一类新型内源性非编码RNA分子，通过剪接形成共价闭合连续环状结构，对于各种疾病的发展、进展、临床诊断和治疗起着重要作用。最近，在骨肉瘤中已经发现了越来越多的环状结构。了解它们在骨肉瘤中的作用对于早期检测、诊断和治疗该病具有优势。circRNA的主要功能涉及其与miRNA的特异性结合能力，尽管它们的生物学功能还扩展到与蛋白质的相互作用、调控基因转录和作为翻译模板的作用。在本综述中，我们探讨circRNAs在骨肉瘤发病机制和进展中的机制和临床应用，特别强调circRNAs作为miRNA海绵在骨肉瘤发展中的调控机制和功能。© 2023. 本文作者，独家许可给Springer Science+Business Media, LLC，Springer Nature的一部分。

Osteosarcoma, the most prevalent primary malignant bone tumor and the third most frequent cancer in children and adolescents worldwide, still poses a significant therapeutic challenge. Even though combined chemotherapy and surgical resection have improved survival rates up to 60%, the prognosis for most patients with metastatic osteosarcoma continues to be dismal. The specific pathogenesis and key regulators of tumor invasion and metastasis remain largely elusive. Circular RNAs (circRNAs), novel endogenous non-coding RNA molecules that form covalently closed continuous loops through splicing, play a crucial role in the development, progression, clinical diagnosis, and treatment of various diseases. Recently, an escalating number of circular structures have been identified in osteosarcoma. Understanding their role in osteosarcoma is advantageous for early detection, diagnosis, and treatment of this disease. The primary function of circRNA involves its unique ability to bind specifically to miRNA, although their biological functions also extend to interacting with proteins, regulating gene transcription, and serving as translation templates. In this review, we explore the mechanisms and clinical applications of circRNAs in the pathogenesis and progression of osteosarcoma, with a particular emphasis on the regulatory mechanisms and functions of circRNAs as miRNA sponges in osteosarcoma development.© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.