Quarter of U.S. Men Have Protein Linked to Cancer

A quarter of men have high levels of a growth protein linked to a greater likelihood of prostate cancer, says a new study that may point scientists toward ways to reduce the incidence of the cancer.

Dr. Michael Pollak of McGill University, who coauthored the study with Harvard University scientists, said if the new research is confirmed, doctors may one day use the protein to better predict which men will one day get cancer.

It’s too early for men to seek testing for the protein, called IGF-1, Pollak said. But he has begun animal studies to test whether drugs that lower its level could prevent men from getting the disease.

“This research finding was a big surprise,” Pollak said. “It opens up a whole new direction of research.”

The study, published in today’s edition of the journal Science, also raised a red flag for men who take growth hormones to fight the effects of aging: That still-experimental trend, hyped on the Internet, may raise their risk of prostate cancer because growth hormone raise IGF-1 levels.

Pollak said taking growth hormones “is, on the basis of our data, a risky business.”

An IGF-1 link to prostate cancer makes sense because doctors have long advised people to lose weight to lower the risk of various cancers--and overeaters have high IGF-1 levels, he said.

Preliminary evidence also has been found that IGF-1 spurs prostate tumors to be more aggressive, a link Dr. Otis Brawley, a prostate cancer expert at the National Cancer Institute, wants studied quickly. If confirmed, it could shed light on why black men die of prostate cancer more than whites--because blacks typically have higher IGF-1 levels, he said.

About 184,500 American men will get prostate cancer this year, and about 39,000 will die, the American Cancer Society estimates.