Despite significant advances in cancer therapy strategies, breast cancer is one of the most common and lethal malignancies worldwide. Characterization of a new class of RNAs using next-generation sequencing opened new doors toward uncovering etiopathogenesis mechanisms of breast cancer as well as prognostic and diagnostic biomarkers. Circular RNAs (circRNAs) are a novel class of RNA with covalently closed and highly stable structures generated primarily from the back-splicing of precursor mRNAs. Although circRNAs exert their function through various mechanisms, acting as a sponge for miRNAs is their primary mechanism of function. Furthermore, growing evidence has shown that aberrant expression of circRNAs is involved in the various hallmarks of cancers. This paper reviews the biogenesis, characteristics, and mechanism of functions of circRNAs and their deregulation in various cancers. Finally, we focused on the circRNAs roles as a sponge for miRNAs in the development, metastasis, angiogenesis, drug resistance, apoptosis, and immune responses of breast cancer.

中文翻译：

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环状 RNA 与 miRNA 的相互作用：在乳腺癌中的新作用

尽管癌症治疗策略取得了重大进展，但乳腺癌仍然是全世界最常见和致命的恶性肿瘤之一。使用新一代测序对一类新的 RNA 进行表征，为揭示乳腺癌的发病机制以及预后和诊断生物标志物打开了新的大门。环状 RNA (circRNA) 是一类新型 RNA，具有共价闭合且高度稳定的结构，主要由前体 mRNA 的反向剪接产生。尽管 circRNA 通过多种机制发挥其功能，但作为 miRNA 的海绵是其主要的功能机制。此外，越来越多的证据表明，circRNA 的异常表达与癌症的各种特征有关。本文综述了 circRNA 的生物发生、特征、功能机制及其在各种癌症中的失调。最后，我们重点研究了 circRNA 作为 miRNA 的海绵在乳腺癌的发育、转移、血管生成、耐药性、细胞凋亡和免疫反应中的作用。