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Cancer Matters


What is PSA?

William G. Nelson
William G. Nelson, M.D., Ph.D.

“PSA, or prostate specific antigen, is an enzyme that normally appears in the ejaculate or central reproduction but when there’s a cancer present, it leaks into the circulation system so you can detect it in the bloodstream, where it becomes a marker of prostate cancer and other prostate diseases,” explains William G. Nelson, M.D., Ph.D., director of the Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins. “Studies show that PSA starts to rise many years before prostate cancers are diagnosed, so finding an abnormal PSA that increases year after year might be a hint that prostate cancer is afoot.”

Listen to the Cancer News Review podcast with Dr. Nelson.