British researchers have developed what they call a three-in-one blood test for advanced prostate cancer — one that helps doctors select an initial treatment, check whether it is working, and monitor the disease long term. The test grew out of research on levels of cancer DNA in patients' blood, which scientists call circulating DNA levels. Higher levels can indicate the disease is progressing. Researchers developed the test to help doctors tailor therapies for prostate cancer stemming from an inherited BRCA gene mutation. They hope it leads to treatment improvements. Researchers from two London research facilities — the Institute of Cancer Research and the Royal Marsden National Health Services Foundation Trust — conducted the study. The article they wrote, "