A simple-to-take test that tells if you have a tumor lurking, and even where it is in your body, is a lot closer to reality -- and may cost only $500. From a report: The new test, developed at Johns Hopkins University, looks for signs of eight common types of cancer. It requires only a blood sample and may prove inexpensive enough for doctors to give during a routine physical. "The idea is this test would make its way into the public and we could set up screening centers," says Nickolas Papadopoulos, one of the Johns Hopkins researchers behind the test. "That's why it has to be cheap and noninvasive." Although the test isn't commercially available yet, it will be used to screen 50,000 retirement-age women with no history of cancer as part of a $50 million, five-year study with the Geisinger Health System in Pennsylvania, a spokesperson with the insurer said. The test, detailed today in the journal Science, could be a major advance for "liquid biopsy" technology, which aims to detect cancer in the blood before a person feels sick or notices a lump. That's useful because early-stage cancer that hasn't spread can often be cured.