TUESDAY, Feb. 24 (HealthDay News) -- Levels of a protein doctors examine to help determine the likelihood of a man developing prostate cancer predicts chances of the disease occurring in blacks just as well as in whites, a new study shows.

The finding is reported in the Feb. 24 issue of Cancer Prevention Research.

High levels of prostate-specific antigen (PSA), which cells in the prostate produce, often indicates an increased risk of cancer in the gland, causing doctors to consider a biopsy when the level exceeds 4 ng/mL. The incidence of prostate cancer in the United States is greatest among black men.

"It was previously thought that PSA levels were just naturally higher in African-American men, suggesting a need to possibly adjust the threshold upward before recommending a biopsy," Dr. Veda Giri, director of the Prostate Cancer Risk Assessment Program at Fox Chase Cancer Center, said in a news release issued by the journal's publisher.

Giri and fellow researchers at the University of Chicago, studied 646 high-risk men and found no "race-specific" differences in PSA levels based on ancestry as either reported by the participants or based on genetic markers. They also found PSA levels had the same success rate in predicting the development of prostate cancer within three years among both blacks and whites with a family history of prostate cancer.

The findings still need to be confirmed through larger studies.

"African-American men and men with a family history of prostate cancer should be encouraged to participate in early detection studies to define personalized screening strategies that may diagnose prostate cancer at a curable point," Giri said.

More information

The U.S. National Cancer Institute has more about prostate-specific antigen levels.