Medical memo

Autoantibody signatures: A promising new test for prostate cancer

Modern medicine has made great strides in the fight against cancer, especially in finding improved ways to diagnose the disease. Not too long ago, many malignancies were diagnosed only after they grew large enough to make people seriously ill or produce a lump or mass that doctors could feel. Next, x-rays were used to detect smaller tumors, and now nuclear scans, CT scans, and MRIs can diagnose much smaller, earlier growths. But as good as they are, these tools are not always good enough, so scientists are turning to biomarkers for even earlier diagnosis.

The prostate-specific antigen (PSA) is a biomarker, a protein produced by prostate cancer cells that can be detected and measured in a man's blood. PSA testing is currently the best way to detect prostate cancer, but it's imperfect. Part of its limitation stems from the fact that all prostate cells, benign and malignant, produce PSA. So while men with prostate cancer tend to have higher blood PSA levels than men without the disease, there is considerable overlap, resulting in many false-positive and false-negative results.