Summary

The basic principle of RNA interference, a possible new therapeutic tool, involves de-struction of messenger RNA upon interaction with homologous double-stranded RNA present in the cell cytoplasm. Studies have shown that both viral and non-viral small in-terfering RNA delivery methods and delivery of chemically synthesized small interfering RNAs to the cell can provide selective gene suppression through this mechanism, both in vitro and in vivo. Before becoming a functional therapeutic tool, there are a number of problems concerning RNA interference that should be solved. Major problems involve off--target effects, insertional mutagenesis and malignant transformation, as well as problems of delivery methods and reduction of toxicity. Key words: RNA interference, small interfering RNA, off-target effects, therapeutic