Abstract
Knocking down a human gene by RNA silencing has been the focus of a number of laboratories since the discovery of the RNAi mechanism more than 10 years ago. In their remarkable work, M. Davis and collaborators show for the first time the induction of an RNAi pathway in humans following systemic administration of nanoparticles. In a clinical trial, they demonstrate the accumulation of the particles in the tumor, as well as the downregulation of mRNA and protein expression of the target gene. Moreover, they successfully linked these observations to the induction of mRNA cleavage by the delivered siRNA in the tumor.