So far, RNAi has been used to inhibit virus-induced diseases (for example HIV [35] and influenza [36]), oncogenic K-ras, H-ras-induced tumorigenesis [37,38], activation of oncogenes resulting from chromosomal translocations (for example bcr/abl in chromic myeloid leukemia [39]), cancers caused by viral infections [40], and so on. The gene discussed is KRAS; the disease is viral infectious disease.