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"Silenced Gene Suggests Greater Risk for African-Americans with Prostate Cancer

By Steve Tokar, UCSF News Services | June 16, 2005

Among African-Americans with prostate cancer, a tumor-suppressing gene called GSTP1 is inactivated at a rate 3.5 times higher than among Caucasians, according to a study conducted at the San Francisco VA Medical Center (SFVAMC).

"This could be one of the mechanisms for the higher incidence of prostate cancer in African-Americans compared to Caucasians," said Rajvir Dahiya, PhD, Director of the Urology Research Center at SFVAMC and the principle investigator of the study. "When tumor suppression activity goes down, the tumor progresses much faster."

In the United States, African-Americans have almost 1.7 times the incidence and mortality of prostate cancer compared to Caucasians (272 per 100,000 vs. 164 per 100,000, respectively).

Researchers found that the GSTP1 gene is temporarily inactivated, or "silenced," through the process of hypermethylation, in which methyl groups (CH3) replace hydrogen atoms (H) in cytosine, one of the four protein bases of the gene's DNA.

Read more at Steve Tokar, UCSF News Services