Colon Cancer Added to Gene Mutation Testing
July 19, 2012 | Dagny Stuart
Vanderbilt-Ingram Cancer Center has initiated tumor mutation testing for a limited number of patients with metastatic colorectal cancer.
This pilot project for colorectal cancer is part of VICC’s Personalized Cancer Medicine Initiative (PCMI), a program to identify genetic mutations in a patient’s tumor that may be useful in matching the appropriate therapy with each patient. VICC patients with lung cancer, breast cancer and melanoma already have their tumors tested for specific mutations, and now some colorectal cancer patients will be added as part of a pilot program.
“We’re testing a panel of eight genes, including mutations in the KRAS and BRAF genes,” said Emily Chan, M.D., Ph.D., assistant professor of Medicine and clinical director of GI Oncology. “What we’re looking at are genes that are known to be mutated in some colorectal cancers. Companies are already developing drugs that block the molecular pathway that gets activated in some of these gene mutations. Other genes don’t have drugs available at the moment, but that doesn’t mean they won’t down the road.”
Chan points to the drug vemurafenib, which has shown strong results in many melanoma patients with the BRAF mutation. About 10 percent of colorectal cancer patients also have the BRAF mutation in their tumor.
“We have participated in a trial looking at a small group of colorectal cancer patients and we did not see the same impressive responses that were seen in melanoma, which lets us know that colorectal cancer is a different disease than melanoma, and vemurafenib by itself doesn’t get the same impact. So it may need to be given in combination with something else. Knowing more about the different mutations within the tumor may help guide us to what may be the best treatment combination for a particular patient,” Chan said.
Some of the mutated genes may serve as prognostic markers to predict how patients will respond to a specific therapy. The results may also help VICC physicians match patients to clinical research trials that target certain molecular pathways in the tumor.
The gene tests are conducted on tissue samples from the patient’s tumor. To participate, patients must have enough tissue available for testing and they must sign a consent form to allow for the mutation testing. About 200 patients will be tested during this initial colorectal cancer program and the results will be evaluated for future projects.
“I have patients who are very interested in getting this testing done, even if they’re on some current therapy because they’re trying to plan for the future. The other thing I hear from patients is even if it doesn’t help them it may help someone in the future, so there’s an altruistic aspect to their willingness to help, as well,” said Chan.
Learn more about the Cancer Center’s PCMI program or call the patient Access Center at (877) 936-8422.