Colon cancer drugs being studied by Huntsman Cancer Institute

SALT LAKE CITY — Researchers at the Huntsman Cancer Institute are using a new $12.2 million grant to test two medications that may help prevent colon cancer.

The drugs are designed to regress the growth of polyps that lead to the deadly disease, said Dr. Randall Burt, the institute's senior director of prevention and outreach. The new grant will fund a double blind, placebo controlled prospective study of how the medications work in people whose inherited chance of developing colon cancer ranges from 80 percent to 100 percent without therapy, he said.

"These folks have inherited a mutation in the APC gene" that means they "get hundreds and thousands of polyps because it's in every cell of their colon."

APC —Adenomatous polyposis coli — is a gene that prevents tumors from forming. It mutates in up to 85 percent of colorectal cancers and adenomatous polyps. Burt was a member of the team that originally discovered the APC gene in the late 1980s.

If the medications are successful in treating the high-risk patients, "the next step would be to give them to those with a more modest increased risk for cancer, and eventually we may even consider giving them to the entire population," as health officials now do with vaccines to prevent disease.

Burt said the developments are promising in the wider population because "80 percent of all colon cancers arise from mutations of this same gene, but they're not inherited mutations." The mutations arise in a single cell that grows a polyp that can develop into colon cancer.

In Utah about 700 new cases of colon cancer are diagnosed annually, Burt said, noting Huntsman treats approximately one-third of those patients.

Colorectal cancer is the third leading cause of cancer-related death in the U.S., and it is also the third most common cancer diagnosed, excluding skin cancer.

The American Cancer Society estimates there were 106,100 new cases of colon cancer (52,010 in men and 54,090 in women) and 40,870 new cases of rectal cancer (23,580 in men and 17,290 in women) nationwide last year.

The lifetime risk for developing colorectal cancer is about 1 in 19, and it is slightly higher in men than women.

The new multimillion-dollar grant for the new medication study at Huntsman follows a similar grant made in 2003 from the National Cancer Institute. Burt said researchers used that grant to lay the foundation for the new research.

"We found several cellular pathways — signaling pathways — that were disrupted by mutations of the APC gene. The medications we're going to use for our clinical trial correct those very signaling pathways that are perturbed by the mutation," he said.

The new research also will look at details of those pathways, which tell cells how to grow, how to die and how to mature.

The previous studies used human tissues, zebra fish, human cell cultures and mice, he said. "They weren't done on the human body itself like we'll do this time (with the clinical trials) but from biopsies taken from tissues with certain inherited conditions."

e-mail: carrie@desnews.com