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December 15, 2011

Vaccine Attacks Breast Cancer in Mice

by Art Chimes

Experimental protein treatment might protect against other tumors

Scientists have developed a vaccine which reduces breast cancer tumors in mice. The researchers say it may work against a number of other cancers, too, if it works in humans.

Vaccines boost the body's immune system to fight off a foreign invader. That makes sense if the invader really is foreign - like influenza or malaria. But Mayo Clinic researcher Sandra Gendler notes that cancers are a home-grown threat - our bodies’ own cells run amok - not an alien virus.

"That's one of the major problems, is that we are tolerant to many of our cancers, and it is difficult to break that tolerance."



So Gendler and her colleagues are focusing on a vaccine based on a protein called MUC1 that occurs on the surface of various kinds of tumors.

"One of the advantages of a MUC1 vaccine is that virtually all solid tumors express it: breast cancer, lung cancer, colon cancer, ovarian cancer, bladder cancer, multiple myeloma, some lymphomas. It has really wide applicability," she said.

Researchers at the University of Georgia, led by Geert-Jan Boons, developed a vaccine based on MUC1 that was tested on special mice that Gendler developed. Her mice produce human MUC1 on tumors, making it a more realistic test for the experimental vaccine.

In the lab, the mice were vaccinated, then injected with breast cancer cells.

"We then monitor for the tumor growth," Gendler said, "and we found that the animals had a large decrease in the tumor growth, about a 75-80 percent decrease in their tumor growth."

So, much smaller tumors compared with the control group of non-vaccinated mice.

If this turns out to be an effective vaccine in humans, Gendler says it might be used to help reduce the risk of cancer before it develops, for example, in women with a high risk of breast cancer. It might also be used alongside existing treatments after diagnosis, particularly for a fast-moving disease like pancreatic cancer.

Gendler, whose research is published online by the Proceedings of the National Academy of Sciences, says human tests might begin as soon as about two years from now.