Cancer is the number one cause of death in Japan. Among the many new cancer treatments currently being researched, a method that uses viruses to kill cancer cells is attracting particular attention. This surprising method, using a pathogen to fight cancer, is made possible by a very common virus: herpes. The genes of the herpes virus are recombined to render it harmless to healthy cells, but deadly to cancer cells. In animal experiments, scientists altered just three of herpes's genes, but this small change created a virus with powerful anti-cancer properties. Human clinical tests are now underway. Will this method become a common form of cancer treatment? Join us as we investigate.