Landscape of Circular Ribonucleic Acids in Urological Cancers

Urological malignancies are among the most important neoplastic diseases imposing a significant burden on health care systems globally. The current therapeutic measures for these cancers have unsatisfactory results, and comprehensive knowledge of pathways involved in carcinogenesis and progression of these cancers is of utmost importance. Circular Ribonucleic Acids (circRNAs) are a class of non-coding RNAs characterized by their single-stranded covalently closed loops, which exert their regulatory effects mainly by sponging the microRNAs (miRNAs) associated with the regulation of gene expression. In the past few years, several circRNAs have been identified to be implicated in the malignancies of the urinary system. A number of these circRNAs are involved in the common carcinogenic pathways, such as MAPK/ERK, TGF-β, and PI3K-Akt pathways. However, further studies are required to ascertain the exact mechanism of numerous circRNAs in urological cancers and determine their diagnostic, prognostic, and therapeutic roles in patients with these cancers.