Contributed by Nicole Weaver| 09 June, 2005 22:31 GMT
Mayo Clinic researchers have discovered a mechanism that blocks the body’s natural ability to reject breast cancer, they announced today, and they have developed an experimental therapy to remove that block.
The Mayo team announced their findings in a news conference at a major gathering of breast cancer specialists, the "Era of Hope" Department of Defense Breast Cancer Research Program meeting in Philadelphia.
New Therapy Boosts Immune System
The goal of the ongoing research is to prevent breast-cancer recurrence in women who already have experienced remission of the disease. In cases where cancer has spread outside the breast, the 10-year relapse rate can be as high as 90 percent, the researchers note.
The Mayo Clinic team and colleagues at the University of Washington showed that their experimental therapy to remove the block did not harm the immune system -- in fact, it boosted it.
Mice that received the toxic injections that killed the immune system blockages had tumors that were one-tenth the size of mice that did not receive the injections.
Breast-cancer researchers have known for years that the body’s immune system naturally is designed to reject breast cancer. However, something interferes with this rejection in breast cancer patients, allowing the cancer to grow unchecked. This new finding helps unlock that mystery and may lead to safer, gentler therapies, suggest the researchers.
"Evidence is emerging that some of the effects of chemotherapy are due to depleting T-regulatory (T-reg) cells," says Keith Knutson, Ph.D., the Mayo Clinic immunology researcher who led the study. "The strategy we use in our investigation may actually be a way to target the T-regs directly, without using the indirect route of chemotherapy. Depleting T-regulatory cells may boost natural immunity against breast cancer."
Role of T-Reg Cells
The Mayo Clinic and University of Washington collaborative study, say the researchers, is the first to show these two new important aspects of breast cancer:
T-regulatory cells play a disease-promoting role in breast cancer.
T-regs can be selectively and therapeutically eliminated without harming the immune response of white blood cells. Instead, blocking T-regs boosts natural immunity.
Further studies must validate these findings before they can be applied to human breast-cancer patients, Dr. Knutson emphasized. Even so, this is a welcome research advance, he says, because breast cancer is the most commonly diagnosed non-skin cancer in women.
This year, more than 211,000 women will be diagnosed with breast cancer in the United States, and 43,300 will die from it, according to the http://National Breast Cancer Foundation. |
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