Can a new vaccine prevent colon cancer?

Futurity In clinical trials, a first-of-its-kind vaccine successfully prompted the immune system to respond to early indications of colon cancer in people at high risk for the disease.

"This prophylactic colon cancer vaccine boosts the patient’s natural immune surveillance, which potentially could lead to the elimination of premalignant lesions before their progression to cancer,” says Olivera Finn, distinguished professor and chair of the Department of Immunology at the University of Pittsburgh’s School of Medicine, who developed the vaccine. “This might spare patients the risk and inconvenience of repeated invasive surveillance tests, such as colonoscopy, that currently are used to spot and remove precancerous polyps."

Colon cancer takes years to develop and typically starts with a polyp, which is a benign but abnormal growth in the intestinal lining. Polyps that could become cancerous are called adenomas and typically are removed before cancer develops.

Results of the first human clinical trials are reported online and in the January issue of the journal Cancer Prevention Research. The study involved people with a previous history of an advanced adenoma, which places them at higher risk for subsequent colorectal cancer.

“Around 30 to 40 percent of these patients will develop a new polyp within three years,” says Robert E. Schoen, professor of medicine and epidemiology with the Division of Gastroenterology, Hepatology, and Nutrition, and clinical leader of the study.

“In this study, we demonstrated the ability of the vaccine to boost immunity. Subsequent trials need to evaluate the vaccine for its ability to lower or prevent polyp recurrence and thus progression to colon cancer.”

The vaccine is directed against an abnormal variant of a self-made cell protein called MUC1, which is altered and produced in excess in advanced adenomas and cancer.  MUC1 also is abnormally present in pancreatic, breast, lung, and prostate cancer and will be tested in the future in patients with premalignant lesions leading to some of those cancers.

To date, no vaccine based on cell proteins made by tumors has been tested in humans to prevent cancer. Preclinical models show the vaccine works by targeting the abnormal cells that grow the cancer.

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