Oncomir
An oncomir is a microRNA that is associated with cancer. MicroRNAs are short RNA molecules about 22 nucleotides in length. Essentially, miRNAs specifically target certain messenger RNAs to prevent them from coding for a specific protein. The dysregulation of certain microRNAs has been associated with specific cancer forming events. Many different oncomirs have been identified in numerous types of human cancers. Oncomirs are associated with carcinogenesis, malignant transformation, and metastasis. Some oncomir genes are oncogenes, in that overexpression of the gene leads to cancerous growth. Other oncomir genes are tumor suppressors in a normal cell, so that underexpression of the gene leads to cancerous growth.Wikipedia