12/13/2011 03:08 pm ET | Updated Dec 21, 2011

Promising Cancer Vaccine Could Shrink Tumors By 80 Percent

Scientists have devised a new, experimental vaccine that seems to be effective at shrinking cancerous tumors in mice by up to 80 percent.

The vaccine worked at shrinking similar mouse versions of breast and pancreatic tumors, but researchers from the University of Georgia and the Mayo Clinic said that it could be applied to other cancers, too, including colorectal and ovarian cancers and multiple myeloma.

Scientists have been working for decades to find a way to mobilize the immune system to be able to identify cancerous cells. The problem has always been that the immune system doesn't recognize the cancerous cells as dangerous because they originated from the body in the first place, and therefore doesn't attack them, researchers said.

But the new vaccine works by targeting the sugar coating of a protein called MUC1 located on the surfaces of the cancerous cells. The sugar coating differentiates the cancerous cells from normal, healthy cells. The mice were engineered so that their cancer cells overexpressed MUC1, just like human cancer cells do.

"This is the first time that a vaccine has been developed that trains the immune system to distinguish and kill cancer cells based on their different sugar structures on proteins such as MUC1," study researcher Sandra Gendler, a professor at the Mayo Clinic, said in a statement. "We are especially excited about the fact that MUC1 was recently recognized by the National Cancer Institute as one of the three most important tumor proteins for vaccine development."

The study will appear in the journal Proceedings of the National Academy of Sciences.

The vaccine has potential to be used on a wide variety of cancers because more than 70 percent of deadly cancers have the MUC1 protein, researchers said. AOL Lifestyle reported that researchers hope to try the vaccine in humans in the next couple of years.

And because MUC1 is overexpressed in 90 percent of people who were unresponsive to other therapies like Tamoxifen or Herceptin, the vaccine might in the future be a viable option for people whose cancers are difficult to treat, researchers added.

The experimental cancer vaccines in the works today are different from the preventive vaccines (like ones that ward off cervical cancer-causing HPV), which prevents cervical cancer.

The Daily Beast explains:

By "cancer vaccine," scientists mean something that will stimulate the immune system to attack malignant cells.

Recently, researchers at the National Cancer Institute developed a promising vaccine that seems to stop the spread of metastatic breast and ovarian cancers in humans. The poxviral vaccine even seemed to be effective at completely ridding one person involved in the study of cancer, WebMD reported.

However, the vaccine wasn't as overwhelmingly successful in the other 25 patients -- for some of those people, the vaccine seemed to extend the amount of time before the cancer progressed by a few months, WebMD noted.

And earlier this year, University of Pennsylvania researchers announced a leukemia treatment that seems effective at obliterating leukemia cells, and was shown to completely rid patients of the cancer or at least significantly decrease their number of cancerous cells.