Researchers at Duke University, USA, are using a genetically-engineered poliovirus to attack and kill cancer cells. It appears that poliovirus receptors are present in great numbers on the surfaces of many types of cancer cells but not on the surfaces of normal cells. The Sabin-type vaccine genome is rendered inactive by removing a section and splicing in a segment of common cold virus genome. The resulting virus cannot cause polio but is still able to effectively attack and destroy cancer cells. Its action also activates the immune system, drawing other cancer-fighting cells such as macrophages (upper center) and leucocytes (lower left) to the area. Labeled.