Vaccine to prevent colon cancer tested

PITTSBURGH, March 20 (UPI) -- U.S. researchers are testing a vaccine to prevent colon cancer in those already at high risk for the disease.

Unlike other anti-cancer vaccines that block viruses, this vaccine has been directed against a variant of a cell protein -- called MUC1.

Colon cancer typically starts with an abnormal growth in the intestinal lining -- a polyp. Polyps that become cancerous are called adenomas. Adenomas produce MUC1 in excess.

"By stimulating an immune response against the MUC1 protein in these precancerous growths, we may be able to draw the immune system's fire to attack and destroy the abnormal cells," principal investigator Dr. Robert Schoen of the University of Pittsburgh School of Medicine said in a statement. "That might not only prevent progression to cancer, but even polyp recurrence."

A dozen people have received the experimental vaccine so far, and the researchers intend to enroll another 50 participants between 40 and 70 years old with a history of adenomas sized 1centimeter or more.

After an initial dose of vaccine, the study participants get doses two and 10 weeks later. Blood samples at those time points as well as 12 weeks, 28 weeks and one year later measure immune response.