Molecular mechanisms of circular RNA in breast cancer: a narrative review

Abstract

Background and Objective Breast cancer is presently the most prevalent cancer and the leading cause of cancer-related deaths in women worldwide. Circular RNA (circRNA) is a class of closed circRNAs lacking a 5'-end cap structure and a 3'-end polyA tail, which is highly stable and widely involved in a variety of pathophysiological processes such as cell proliferation, differentiation, and apoptosis. In recent years, accumulating studies have shown that circRNAs play an important role in the development and prognosis of breast cancer, but there are fewer literature reviews on their intrinsic molecular mechanisms which is the aim of this study. Methods This review synthesizes the findings of literature retrieved from searches of PubMed and Google Scholar databases, hand searches, and authoritative texts. Citations mainly originate from the past 3 years. The articles need to describe the role of circRNA in breast cancer; no language restrictions were imposed. Key Content and Findings This review summarizes the latest relevant literature and systematically reviews the four main mechanisms of circRNA in breast cancer from the perspective of circRNA function. At the same time, we describe the formation mechanism, characterization, and biological functions of circRNAs. Conclusions We reviewed the status of actual knowledge about circRNA biogenesis and functions and summarized novel findings regarding the molecular mechanism of circRNA in breast cancer. Meanwhile, this review explores the possibility of circRNAs for becoming new biodiagnostic indicators and therapeutic targets in breast cancer.