Could genes be a licence to smoke? DNA therapies will change the way cancer is treated – and how tobacco firms sell cigarettes, says Nick Horley. Last Updated: 8:41PM GMT 08 Dec 2008 Revolution in genetic science could soon identify those at least and greatest risk of certain diseases such as smoking-related lung cancer Photo: BLOOMBERG The management and treatment of cancer is one of the most important – and expensive – duties of the NHS. But did you know that of the £1 billion spent on providing chemotherapy every year, half goes straight down the drain? The reason is that our medical techniques are essentially based on guesswork. Often, doctors prescribe drugs that have no benefit. They cannot kill the tumour’s cells because they are not targeted at its specific genetic profile. Yet now the revolution in genetic science offers the chance to have treatments tailored to our personal