A Vaccine May Aid Colon Cancer Prevention in the Future

Preventive vaccines may be the next step forward in keeping away colorectal cancer, which is the third leading cause of cancer-related deaths for both men and women living in the United States.

Today, screening tests, such as a colonoscopy, can help detect colorectal polyps, which doctors can remove before such growths turn cancerous. Screening can also help find colorectal cancer at an early stage, when it is easier to treat.

Even though screening can be successful in helping to prevent colon cancer, there are still many people – especially those at an increased risk – who get and die from colorectal cancer.

To strengthen prevention efforts, Mary (Nora) Disis, M.D., a researcher at the University of Washington, is trying to create a vaccine that could help a person’s immune system ward off the formation of colon cancer.

Disis and her team are working to identify genes that they could put into a vaccine that would spur the body to generate the type of immune cells needed to kill cancer cells just as they are starting to develop.

“We have identified a couple hundred genes that would be reasonable targets for a prevention vaccine,” says Disis. Now she has to figure out which of these genes “would be useful or important to include in a cancer vaccine.”

With the help of a just-awarded American Cancer Society Clinical Research Professor grant, Disis says her next steps are to determine which of the genes are important in the growth of cancer and to understand whether a person’s immune system will recognize these genes, and the proteins they encode, which is necessary for the vaccine to work.

“We are in the screening phase now, but we hope that with the help of the American Cancer Society grant that we will be able to accelerate getting testing into mice pretty quickly,” Disis says. “We think it will take about 3 years to be able to sort through all our [gene] candidates and come up with a vaccine to show efficacy in mice; from there it will take another year to do extensive testing to make sure it would be safe to do human clinical trials.”

If proven safe and effective, Disis sees this potential vaccine as being particularly useful in people who are at high risk of developing colorectal cancer, such as those who have a family history or polyposis syndrome. “I see this vaccine as being given in conjunction with other treatments associated with preventing the progression of polyps to cancer,” says Disis.