Noncoding RNAs and Colorectal Cancer: A General Overview

Colorectal cancer (CRC) is the second most prevalent cancer in the world in which nonmelanoma skin cases are not considered. Different epigenetic mechanisms play a role in the development of cancer. Noncoding RNAs (ncRNAs) are RNA molecules transcribed from noncoding regions of the genome. These are divided into sncRNAs (small noncoding RNAs: <200 nucleotides - including miRNAs [microRNAs], siRNAs [small interfering RNAs], piRNAs [piwi-interacting RNAs], snoRNAs [small nucleolar RNAs]) and lncRNAs (long noncoding RNAs: >200 nucleotides - includingcircular RNAs [circRNAs]). NcRNAs can act as oncogenes or as tumor suppressor genes in CRC and are potential biomarkers of diagnosis, with possible clinical implications. This article aims to conduct a general review of all types of non-coding RNAs and their influence in colorectal cancer, focus on biomarkers of CRC and their possible applications in clinical practice, as well as review their biogenesis and functions. Furthermore, we seek to summarize possible databases available for new searches and studies that require sequence annotation, comparison sequences and target prediction for ncRNAs with the hope of gathering information that can aid in the process of understanding and translating the use of ncRNAs into clinical practice.