A second study found that men with lots of HDL, or "good cholesterol," were a little less likely to develop any form of prostate cancer than men with very low HDL.

Both studies were published Tuesday in Cancer Epidemiology Biomarkers & Prevention, a journal of the American Association for Cancer Research.

The two studies are not definitive and have some weaknesses. Yet they fit with plenty of other science suggesting that limiting fats in the bloodstream can lessen cancer risk.

"There might be this added benefit to keeping cholesterol low," said Elizabeth Platz of Johns Hopkins University.

She led the first study, which looked at 5,586 men aged 55 and older who were in the placebo group of a big federal cancer prevention study done in the 1990s.

Cholesterol levels made no difference in the odds of getting prostate cancer except for the 60 men who developed high-grade tumors, the type that grow and spread fast. The chance of developing one of these aggressive tumors was 59 percent lower among men with cholesterol under 200.

That's "a striking reduction in risk," Eric Jacobs and Susan Gapstur, epidemiologists with the American Cancer Society, write in an accompanying editorial.

Now for the caveats: Researchers do not know how many men in the study were taking statin drugs such as Lipitor, Zocor or Crestor. That means some of the reduced cancer risk could have come from these cholesterol-lowering medicines instead of from low cholesterol by itself.

Previous reports also suggest that statins can lower cancer risk, but it's premature to take them for this reason until better studies are done, doctors advise. Statins have long been known to prevent heart disease, and nothing about the new research changes that.

The second study involved more than 29,000 Finnish men more than a decade ago. The men, all smokers, were testing whether various vitamins and nutrients could lower their cancer risk.

Those with highest levels of HDL were 11 percent less likely to develop prostate cancer than those with lowest levels, said study leader Dr. Demetrius Albanes of the National Cancer Institute.

Prostate cancer is the most common cancer in American men. More than 192,000 new cases are expected to occur in the United States this year, leading to an estimated 27,360 deaths.