For the first time, scientists have identified a specific protein on the surface of tumor cells that marks them as being cancer, a discovery that may open an important new approach to diagnosis and treatment, a Belgian research team announced yesterday. The team also identified the gene that makes the marker.
The marker, a so-called antigen designated MZ2-E, seems to result from a gene's being switched on accidentally only in cancer cells, not on normal cells. If that is confirmed, it could mean that scientists have found an "exploitable difference" that may be used to kill cancer cells without harming normal cells, researchers said.
The finding, reported in today's Science, may provide new tools for therapy based on the body's main line of defense against disease, the immune system.
The presence of an identifying protein on cancer cell surfaces that can be "seen" by the immune system's T-cells could lead to new methods for cancer diagnosis.
The discovery was reported by a research team led by biologist Thierry Boon at the Ludwig Institute for Cancer Research in Brussels.
They found the marker on cells of the most dangerous type of skin cancer, melanoma; on lung cancer cells and on some other cancers, drawn from numerous patients. It is too soon to know if the protein marker exists on all cancer cells.
"This demonstrates clearly that you can have the same antigens [surface molecules] on many different tumors carried by different people. So we could possibly try to immunize many people with the same preparation," the biologist said in a telephone interview.