Scientists at the University of Pittsburgh are testing a vaccine to recognize a protein in colon polyps and trigger the immune system to destroy them.
MUC1 is a protein found in precancerous colorectal polyps and in colon cancer. The experimental vaccine causes the body’s immune system to develop antibodies against MUC1, killing tissue that contains it and potentially preventing polyps from returning.
Participants in the Phase II clinical trial have already been diagnosed with an advanced adenoma — a colorectal polyp that has a high risk of becoming cancer. They receive three doses of the vaccine, injected into their thigh. In the 20 patients already enrolled, there haven’t been serious side effects beyond some redness where the injection was given.
Researchers are measuring immune system response to the vaccine including looking forT-cell activity and antibodies against MUC1.
Future colonoscopies will test whether the vaccine reduces new adenomas.
If the vaccine is successful, it could reduce the number of colonoscopies necessary to watch for new polyps in for people with a history of adenomas.
Not all colorectal tumors develop MUC1, so it would still be possible to develop colon cancer, but if the vaccine works, it would reduce the risk. It probably would not replace colonoscopies entirely.
Robert E. Schoen, professor of medicine at the University of Pittsburgh School of Medicine, who is leading the study, explained,
This is taking it in a different direction. We’re now trying to use immunotherapy as a means of prevention. You would be using your immune system as a surveillance mechanism to prevent the development of malignancy.
Contact information is available from Lynda Dzubinski in the Digestive Disorders Clinic at the University of Pittsburgh Medical Center. Call 412-648-9116.
SOURCE: Jocelyn Rice, A Vaccine for Colon Cancer, MIT Technology Review,July 27, 2009.