New and diverse groups of noncoding RNAs are beginning to be discovered. These noncoding RNAs are grouped based on their sizes, genomic positions, or distinctive functions ranging from the regulation of chromatin structure and gene expression to genome stability maintenance. | Turkish Journal of Biology Review Article Turk J Biol (2014) 38: 817-828 © TÜBİTAK doi: Noncoding RNAs and cancer Hesna Begüm AKMAN, Ayşe Elif ERSON BENSAN* Department of Biological Sciences, Faculty of Arts and Sciences, Middle East Technical University, Ankara, Turkey Received: Accepted: Published Online: Printed: Abstract: New and diverse groups of noncoding RNAs are beginning to be discovered. These noncoding RNAs are grouped based on their sizes, genomic positions, or distinctive functions ranging from the regulation of chromatin structure and gene expression to genome stability maintenance. Among noncoding RNAs, microRNAs are the best studied and understood small RNAs with direct and indirect roles in normal and in cancer cells. Given the high rate of transcription from noncoding parts of the genome, other noncoding elements are also of great interest. It is also of interest to understand that there may be interesting cases of crosstalk and/or coregulation between the noncoding and the coding portion of the genome. Therefore, deregulated expression of noncoding RNAs can be considered to cause significant alterations in cancer cells. The complexities of the genome and transcriptome still remain mesmerizing. As we better understand these complexities, we will be able to improve our understanding of human conditions and will hopefully develop tools to improve the ways in which we deal with diseases, particularly cancer. Here, based on recent findings, we provide a descriptive profile of noncoding RNA classes, their roles, and their potential contributions to the complex events of tumorigenesis. Key words: Noncoding RNAs, cancer, long noncoding RNAs, small noncoding RNAs, microRNAs 1. Introduction Following the completion of the human genome a decade ago, we came across a surprisingly low number of proteincoding genes in the human genome compared to the
