Different delivery methods—different expression profiles

Recent publications by several groups of researchers have suggested that small interfering RNAs (siRNA) delivered by lipid-mediated transfection induce both sequence-specific effects1 and broad, class-specific changes in gene expression1, 2, 3, 4. These findings challenge convictions previously held in the RNA interference (RNAi) community that assert virtual sequence specificity of siRNA knockdown, and they bring into question the value of this methodology as a research and therapeutic tool.