MicroRNAs (miRNAs) are small, noncoding RNAs transcribed from DNA that are 18–24 nucleotides in length. A single miRNA has the capacity to regulate a large number of target messenger RNAs (mRNAs), and the main function of miRNAs is to downregulate gene expression. A large set of miRNAs is overexpressed or downregulated in various human cancers compared with normal tissues, and gene silencing by miRNAs enhances tumor malignancies.
Part of the book: Neurooncology