Friday, July 11, 2008 12:00 AM

FRIDAY, July 11 (HealthDay News) -- A protein that appears to suppress the growth of human cancer cells in lab cultures was, until recently, thought topromotecolorectal cancer.

Previous animal studies have found that a gene called TCF7L2 is active in about 90 percent of colorectal cancers because of a biochemical malfunction in a gene. As a result, researchers suspected TCF7L2 triggered colorectal cancer in humans.

New technology used by University of Texas Southwestern Medical Center at Dallas researchers, however, allowed them to study the gene on human colorectal cancer cells. When the researchers switched off the TCF7L2 gene, human colorectal cancer cells actually grew stronger and more rapidly in lab cultures.

"This finding reshapes a fundamental model of how colorectal cancer arises," senior study author Lawrence Lum, an assistant professor of cell biology at UT Southwestern, said in a university news release.

The study was published online in this week's issue of theProceedings of the National Academy of Sciences.

The next step, he said, is to understand more fully all the steps in the biochemical pathway involved in controlling the action of TCF7L2. This may help find new therapeutic targets for treating colorectal cancer.

More information

The American Cancer Society has more about colorectal cancer.

SOURCE: University of Texas Southwestern Medical Center at Dallas, news release, July 7, 2008