A novel way to assembled a targeted cancer therapy: "Cancer is a difficult disease to treat because it's a personal disease. Each case is unique and based on a combination of environmental and genetic factors. Conventional chemotherapy employs treatment with one or more drugs, assuming that these medicines are able to both 'diagnose' and 'treat' the affected cells. Many of the side effects experienced by chemotherapy patients are due to the fact that the drugs they are taking aren't selective enough. ... But what if we had cancer treatments that worked more like a computer program, which can perform actions based on conditional statements? Then, a treatment would kill a cell if - and only if - the cell had been diagnosed with a mutation. Only the defective cells would be destroyed, virtually eliminating unwanted side effects. ... researchers [have] created conditional small RNA molecules to perform this task. Their strategy uses characteristics that are built into our DNA and RNA to separate the diagnosis and treatment steps. ... Here's how it works: Treatment involves two different small RNAS. The first small RNA will open up if - and only if - it finds the cancer mutation. A positive 'diagnosis' exposes a signal that was previously hidden within the small RNA. Once this small RNA is open, a second small RNA binds to it, setting off a chain reaction in which these RNA molecules continue to combine to form a longer chain. The length of the chain is an important part of the 'treatment'. Longer chains trick the cell into thinking it has been invaded by a virus, tripping a self-destruct response."