Unlike any other families of organisms which may be beneficial or even essential to the well-being of each other and the environment, the nature of virus life cycle fated them pathogenic and purely harmful to their hosts. In fact the word "virus" simply means venom (Edward K. Weigner, 1999). But now with a maturing understanding of genetic engineering and recombinant technology, we can expect to create biological therapeutic agents from genetically modified strains of viruses that can overcome difficulties and side effects of existing chemo-therapeutic agents for cancer treatment. These genetically modified members of these simple microorganisms show exceptional potential value as tools to vaccinate against or treat, since such "living" drugs can be specifically designed to attack certain weaknesses of carcinogenic cells and efficiently preventing them from causing sickness.…
