Once again the lure of a “simple” test has made headlines. This time the catalyst was a news release issued by the UK’s National Cancer Research Institute. Its title: “Simple blood test for early detection of breast cancer.” In fact, no such test exists. As the body of the PR news release acknowledged, it’s an idea based on preliminary research. Yet a spate of optimistic headlines appeared. New blood test could detect breast cancer 5 years before symptoms, announced the…