A GM tomato has been portrayed in the world's media as a major cancer fighter, as well as having other important health-enhancing properties. And some media commentators suggest that this is the "breakthrough" that will convince people of the benefits of GM foods. But the health claims are based on a small-scale study of mice, and experts say the results may have occurred by chance, or may simply not be applicable to humans. They also say that there could be problems with toxicity and that these have not been investigated. In any case, a range of existing fruit and vegetables offer the same potential benefits without any need to resort to genetic engineering