Clinical Application of MicroRNAs in Breast Cancer Treatment

Background: Recurrence of breast cancer remains a critical problem. Therefore, it is imperative to identify biomarkers that accurately reflect disease state and develop novel drug therapies that are effective even after recurrence. MicroRNAs (miRNAs) are involved in the malignant transformation of various tumors. Circulating miRNAs are promising biomarkers for the diagnosis and treatment of cancers. Additionally, miRNAs are regarded as next-generation drug targets. Currently, various clinical trials are being conducted for anti-cancer drugs using miRNAs. In this review, we summarized recent studies on miRNA functions and circulating miRNAs in breast cancer, and discussed the status of miRNAs as drug discovery candidates. We also discussed the role of extracellular vesicles (EVs) in the clinical application of miRNAs.Methods: Relevant articles published from 2002 to 2021 were acquired from PubMed database using the following key words: “miRNA” and “breast neoplasia”. Clinical trial data were retrieved from the database, ClinicalTrials.gov.Results: Regulating these miRNAs may provide a new therapeutic strategy. Furthermore, miRNAs may be useful diagnostic and prognostic biomarkers for breast cancer. In addition, miRNAs have potential as anti-cancer agents, and may also be used in combination with other therapies to enhance the efficacies of other drugs.Conclusion: In summary, miRNAs have shown promise as biomarkers and therapeutic targets. In addition, EVs will be the key to expanding the applications of miRNAs.