Mesothelioma: New Vaccine Offers New Hope

Last week the Mayo Clinic published a press release about potentially groundbreaking cancer research that may eventually have a real impact on those suffering with mesothelioma. According to the press release, researchers in partnership at the Mayo Clinic in Arizona and the University of Georgia have successfully tested a vaccine in mice that dramatically reduces the type tumors that make up the majority of cancer cases.

Vaccines are not typically used to treat cancers such as mesothelioma because most vaccines work by stimulating the body’s immune system. Because tumors grow from the body’s own cells, the immune system does not recognize these cells as “foreign,” and essentially ignores them. This vaccine, however, is different, as it can target cancerous cells based on a carbohydrate signature present in the proteins on the surface of the cell. When cancer forms at the cellular level, the surface proteins on the cell membranes change. Specifically, a carbohydrate sequence within the protein changes in a distinct way. For many years researchers have been attempting, with no success, to stimulate the immune system to recognize that difference. This new vaccine may do just that.

The tumors studied in these mice, like most tumors in humans, overproduce a protein known as MUC1 on the cellular surface that contains the type of carbohydrate sequence that changes when the cell becomes cancerous. This new vaccine, for the very first time, targets this carbohydrate sequence and steers the immune system to attack cells that carry that sequence. The vaccine operates in three-part harmony, so to speak, each of which is critical to the success of the vaccine. One aspect of the vaccine helps the body’s immune system to mis-identify the carbohydrate sequence as foreign, while the other two aspects stimulate the antibody and lymphocyte responses. The result is astonishing.

What’s more, not only does this particular vaccine tend to cause a very strong immune response, but also the MUC1 sequence it targets is found in a large majority of cancers that kill, including breast cancer, ovarian cancer, and the historically aggressive pancreatic cancer. The vaccine could potentially be used as a prophylactic treatment for high-risk patients or as an alternative when, in cases like pancreatic cancer, surgery is not an option. According to the study’s co-author Geert-Jan Boons, Ph.D., Franklin Professor of Chemistry and a researcher in the UGA Cancer Center, MUC1 is “overexpressed” in 90 percent of patients who have so-called “triple negative” tumors, in which the tumors are not responsive to drugs or hormone therapy and are therefore very aggressive and difficult to treat.

You may be wondering where mesothelioma fits into this picture. Well, according to a research study published in 2008 by an Australian research team, malignant mesothelioma does result in the overexpression of the MUC1 carbohydrate chain. What this means in the long run for mesothelioma treatment is yet uncertain, but the results of the Mayo Clinic study show great promise for the future. According to last weeks’ press release, the research team is now conducting the preliminary research needed to launch a human trial, and if this stage goes well, human trials could begin as early as 2013.

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