AUTHOR=Xiang Ying , Tian Qing , Guan Li , Niu Shuai-shuai TITLE=The Dual Role of miR-186 in Cancers: Oncomir Battling With Tumor Suppressor miRNA JOURNAL=Frontiers in Oncology VOLUME=Volume 10 - 2020 YEAR=2020 URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2020.00233 DOI=10.3389/fonc.2020.00233 ISSN=2234-943X ABSTRACT=MicroRNAs (miRNAs) are a class of noncoding RNAs in short length which regulate genes expression at post-transcriptional level. Alterations of miR-186 expression were demonstrated in numerous cancers, playing a vital role in oncogenesis, invasion, metastasis, apoptosis and drug resistance. MiR-186 was documented as a tumor suppressor miRNA in the majority of studies, while conflicting reports verified miR-186 as an oncomir. The contradictory role in cancers may impede the application of miR-186 as a diagnostic and therapeutic target, as well as other dual functional miRNAs. This review emphasizes the alterations and functions of miR-186 in cancers, and discuss the mechanisms behind the contradictory findings. Among these, targets abundance and dose-dependent effects of miR-186 are highlighted. It is aimed to remind of challenges in developing diagnostic and therapeutic strategies for cancer treatment based on dual functional miRNAs.