June 23, 2009

Improved cancer risk test developed

U.S. scientists have completed the largest animal toxicology study ever conducted, challenging some concepts concerning cancer-causing compound levels.

Oregon State University researchers said their study found acceptable levels of at least one carcinogen may be 500 to 1,500 times higher than currently believed. The scientists said their findings also indicate for many purposes trout may be a superior animal model to laboratory rats, and that traditional methods of assessing carcinogen risk need to be re-evaluated.

The whole foundation of modern toxicology is that the dose makes the poison, Professor George Bailey said. "You can die from eating a few tablespoons of ordinary table salt at one time, but that doesn't mean table salt is a poison at the doses that humans normally consume.

With compounds that we know can cause cancer, the real question is how much is too much, Bailey added. What we have found is that traditional approaches to making that evaluation, which are almost always based on studies done at very high doses with laboratory rodents, may not always give us answers that are reasonably accurate.

The study that included Assistant Professor Gayle Orner and researchers from the University of North Carolina appears in the journal Chemical Research in Toxicology.