By targeting a protein unique to the prostate gland, researchers may have found a compound that is a safe and effective treatment for prostate cancer and other prostate diseases.

As they age, most men will develop some sort of prostate abnormality, such as enlargement of the prostate or prostate cancer. A drug that is activated by prostate-specific antigen (PSA) "a protein produced by both the normal and diseased prostate gland"could be effective in treating prostate diseases while leaving non-prostate cells unharmed.

Simon Williams, Ph.D., of The Johns Hopkins Oncology Center in Baltimore, and colleagues synthesized a PSA-activated protoxin, called PRX302, and tested it in prostate cancer cells and several animal models. PRX302 caused prostate cancer tumors to shrink when injected directly into mice tumors. Because PRX302 is activated only in the presence of PSA, cells that do not express PSA were unaffected. A phase I clinical trial has already begun to test the toxicity of PRX302.

"The development of novel therapies to treat prostate cancer could be of substantial benefit to large numbers of men," the authors write. "Current therapies for these local recurrences include techniques that are associated with substantial morbidity, including increased rates of incontinence and impotence."

Contact: Samuel Denmeade, Johns Hopkins University School of Medicine

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Other highlights in the March 7 JNCI

Note: The Journal of the National Cancer Institute is published by Oxford University Press and is not affiliated with the National Cancer Institute. Attribution to the Journal of the National Cancer Institute is requested in all news coverage. Visit the Journal online.

Contact: Liz Savage
Journal of the National Cancer Institute