Recent News and Articles on the Keywords: cancer + prostate + clue  Related to the article below (Last Update: 8/7/2008)

A Clue to Racial Differences in Prostate Cancer?

Doctors have long known that prostate cancer is more deadly in African American men and strikes them at younger ages than men of other races. What they don't know is why that's so.

A small pilot study published in The Journal of Urology (Vol. 170, No. 3: 990-993) may offer up a clue.

Researchers at the University of North Carolina, Chapel Hill, found higher levels of androgen receptor protein, a protein that helps stimulate prostate cancer, in tissue samples taken from black men compared to tissue samples taken from white men.

"To my knowledge, this is the first biological difference found between the two races that could explain the difference in aggressiveness of prostate cancer in African American men," said study co-author James Mohler, MD, who left North Carolina in May to become chair of the department of urologic oncology at Roswell Park Cancer Institute in Buffalo, New York.

But, he cautions, it's too early to say for sure that the mystery has been solved.

"This is a very, very preliminary finding -- that needs to be confirmed before anybody attaches any significance to it," he said.

Mohler and his colleagues examined prostate tissue samples from 25 African American men and 25 white men whose prostate had been removed after they were diagnosed with localized prostate cancer. The men were similar in age, and had similar cancer stages and degrees of spread.

The cancerous tissue taken from the black men had 81% more androgen receptor protein than cancerous tissue from the white men. Even the prostate tissue that didn't have cancer had 22% more androgen receptor protein in the African American men.

That means that the normal prostate tissue in this group of African American men was more stimulated to develop cancer, and the cancer that had already developed was more stimulated to grow, Mohler said.

He had not expected to find such a difference. "I was very surprised by these findings, so we're trying to confirm them in a very large study."

Additional study is crucial, agreed Durado Brooks, MD, director of prostate and colorectal cancer at the American Cancer Society. "We certainly need to view this in a much larger group of men," he said.

Future studies must take into account other factors that could influence the development of prostate cancer, like obesity, he said.

Researchers should also compare men of different races who have the same levels of prostate specific antigen (PSA), he added. PSA is a marker of prostate cancer, and African American men with the disease tend to have higher levels of it than white men with prostate cancer. That trend held true in this pilot study, too. Could androgen receptor protein be linked to PSA levels, independent of race?

Until additional studies are completed, Mohler said, there is no way to translate his findings into practical advice for men concerned about prostate cancer.

"I am unsure what the clinical repercussions are of this finding," he said, "and it's certainly premature to even speculate until they're confirmed."

What African American men can do is follow ACS recommendations for the early detection of prostate cancer, Mohler said. African American men are advised to talk with their doctor about prostate cancer screening at age 45, or even younger if they have a strong family history of the disease.

Brooks agreed. "At this point, this study doesn't give us enough information to alter current recommendations, but it does give interesting food for thought and a very interesting direction for future investigators."