AUTHOR=Tran Anh M. , Chalbatani Ghanbar Mahmoodi , Berland Lea , Cruz De los Santos Mireia , Raj Priyank , Jalali Seyed Amir , Gharagouzloo Elahe , Ivan Cristina , Dragomir Mihnea P. , Calin George A. 

TITLE=A New World of Biomarkers and Therapeutics for Female Reproductive System and Breast Cancers: Circular RNAs

JOURNAL=Frontiers in Cell and Developmental Biology

VOLUME=Volume 8 - 2020

YEAR=2020

URL=https://www.frontiersin.org/journals/cell-and-developmental-biology/articles/10.3389/fcell.2020.00050

DOI=10.3389/fcell.2020.00050

ISSN=2296-634X

ABSTRACT=As one of the most recently (re)discovered types of non-coding RNAs (ncRNA), circular RNAs (circRNAs) differentiate from other ncRNAs by a specific biogenesis, high stability and distinct functions. The biogenesis of circRNAs can be categorized into three mechanisms that permit the back-splicing reaction: exon-skipping, pairing of neighboring introns and dimerization of RNA binding proteins. Regarding their stability, circRNAs have no free ends, specific to linear RNA molecules, prompting them a longer half-life and resistance to exonuclease-mediated activity by RNase R, bypassing the common RNA turnover process. Regarding their functions, circular transcripts can be categorized into four broad roles: miRNA sponging, protein binding, regulation of transcription, and coding for proteins and peptides. Female reproductive system (including mainly ovarian, corpus and cervix uteri cancers) and breast cancers are a primary cause of death in women worldwide, accounting for over 1,212,772 deaths in 2018. We consider that a better understanding of the molecular pathophysiology, by studying coding and non-coding RNA regulators, could improve the diagnosis and therapeutics of these cancers. The field of circRNA and breast or gynecological cancers developed only very recently, and most circRNA-related discoveries being made in the last two years. Therefore, in this review we summarize the newly detected roles of circRNAs in female reproductive system (cervical cancer, ovarian cancer and endometrial cancer) and breast cancers. We argue that circRNAs can become essential elements of the diagnostic, and therapeutic tools of female reproductive system cancers in the future.