A new screening test makes use of urine, rather than blood, to identify the men most at risk of prostate cancer, and may even provide information about how aggressive a tumor is likely to be. The standard screening test for prostate cancer is a blood test for a protein called prostate specific antigen (PSA). But PSA is also produced by non-cancerous conditions such as enlarged prostates or infection, so is not very specific....[Arul] Chinnaiyan and his colleagues have developed a new test that detects two markers specific to prostate cancer. One, called TMPRSS2:ERG, is the fusion of two genes, TMPRSS2 and ERG, and is found in around half of prostate tumors found through PSA screening. The other, a non-coding RNA called PCA3, is a very sensitive marker, found in unusually high levels in more than 95% of prostate cancers. The researchers studied 1,065 men [with],,,elevated PSA. They used their test to stratify the men into low-, intermediate- and high-score groups. Biopsies confirmed cancer in 21% of the low-score group, 43% of the intermediate group and 69% of the high group....Futher studies will allow refinement of the test, but the researchers say patients in the high risk group should definitely get a biopsy. High-scoring men with a negative biopsy might also choose to be closely monitored given their high risk. Higher urine test scores also correlated with the aggressiveness of the cancer, as determined by the size of the tumor and a standard metric of cell abnormality called the Gleason score. This is something that biopsies cannot do reliably. The results pave the way for Gen-Probe ...to seek approval from the US Food and Drug Administration (FDA)....But urine-based tests are not likely to replace the PSA test any time soon. "We are initiating long-term, prospective trials to begin gathering enough data to determine whether this test could, one day, serve as a replacement," says Chinnaiyan. "But the bar will be pretty high when attempting to replace a test physicians have used for so long."