Non-coding RNA production by RNA polymerase III is implicated in cancer.

RNA polymerase III (Pol III) makes a variety of small non-coding RNAs, such as tRNA and 5S ribosomal RNA. Increased expression of pol III products is often observed in transformed cells. Much progress has been made in determining how Pol III-dependent transcription is regulated and how it increases in cancers, but the importance of this increase has not been clearly established. New evidence suggests that Pol III output can substantially affect transformation.