The dicey role of dicer: Implications for RNAi therapy

The dynamic properties of RNA interference (RNAi) in cancer biology have led investigators to pursue with significant interest its role in tumorigenesis and cancer therapy. We recently reported that decreased expres-sion of key RNAi enzymes, Dicer and Drosha, in epithelial ovarian cancers was associated with poor clinical outcome in patients. Dicer expression was also functionally relevant in that targeted silencing was limited with RNAi fragments that require Dicer function compared with those that do not. Together, this and other studies suggest that RNAi machinery expression may affect key pathways in tumorigenesis and cancer biology. Under-standing alterations in the functional RNAi machinery is of fundamental importance as we strive to develop novel therapies using RNAi strategies.