Breast cancer cells can destroy a powerful immune response in the body and allow the disease to spread to the patient's bones, researchers in Australia reported on Monday.
They also experimented with two ways to reinstate this immune response to help patients fight breast cancer, but it will take more tests and several more years for these therapies to become routine treatments, they said.
In 2010, 1.5 million people were diagnosed with breast cancer, the top cancer in women around the world. Although it kills many women in developing countries, 89 percent of women diagnosed with breast cancer in western countries are still alive five years after diagnosis thanks to detection tests and treatment.
Using tissue samples from breast cancer patients and experiments with mice, Parker and colleagues found that a gene called IRF7 is switched off in patients whose cancer spreads to other parts of the body. IRF7 controls the production of interferon, an important type of immune protein that fights viruses and bacteria apart from tumor cells. Usually when breast cancer cells leave the breast and travel in the bloodstream and into bone marrow, the release of interferons by IRF7 will cause the immune system to recognize those cells and eliminate them. But by losing IRF7, it prevents the stimulation of immune responses and allows those cells to hide from being recognized.