Antibody Microarray Assay for Prostate Cancer

Researchers have developed an assay based on 22 autoimmune antibody biomarkers to detect prostate cancer with greater sensitivity than the currently used PSA (prostate-specific antigen) test.

Since men with normal blood levels of PSA can have prostate cancer, and PSA-based screening has a high rate of false-positives, scientists have been seeking for new ways to screen for early disease. Investigators at the University of Michigan (Ann Arbor, USA) scanned 2,300 bacteriophages for those that would bind specific anti-prostate cancer antibodies in the serum of patients with prostate cancer. They identified 22 biomarkers, which they used to prepare microarrays. The microarrays were then used to analyze serum samples from 119 patients with prostate cancer and 138 controls.

A statistical analysis of the tests showed that the protein panel performed better in distinguishing between prostate cancer patients and controls than the PSA test. The panel of 22 proteins predicted the presence of cancer accurately in 92.7% of the time, while PSA predicted the presence of cancer only 79.6% of the time. The test showed 88.2% specificity and 81.6% sensitivity. The results were published in the September 22, 2005, issue of the New England Journal of Medicine.

"Initially, we envision this new test could be used as a supplement to PSA. A physician might suggest a patient with an elevated PSA have this test before a biopsy to better determine whether it's a cancerous or benign condition. In the future, I think this could replace PSA,” said senior author Dr. Arul Chinnaiyan, professor of pathology at the University of Michigan Medical School.



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