Typically, the "innate" immune system's Pac-Man-like white blood cells, or leukocytes, engulf and destroy invading microbes when receptors on their surface receive a signal from serum in the blood -- often an antibody produced by a B cell in the separately evolved "acquired" immune system.
Now UCSF researchers have found that in the presence of precancerous tissue, leukocyte antibody receptors can also be activated to turn on a dangerously different program: inducing leukocytes to boost cell growth, increase the number of blood vessels and "remodel" tissue in the area -- all of which help cancer develop.
The finding adds a critical and surprising detail to the emerging view that inflammation, usually a helpful response to invading pathogens, can become misdirected and fuel cancer.
The new research was presented today (February 19) by UCSF scientist Lisa M. Coussens, PhD, at the annual meeting of the American Association for the Advancement of Science (AAAS) in a session titled "healthy aging: inflammation and chronic diseases."
"Immunologists have known for decades that B cells of the so-called adaptive or acquired immune system are activated following a bacterial infection and in response, produce antibodies that signal leukocytes to attack," said Coussens, associate professor of pathology in the UCSF Cancer Research Institute. "But in precancerous tissue in mice, we have found that leukocytes apparently receive signals to switch programs, stimulating cell growth and increasing blood supply -- processes that would normally help healing from an infection, but can instead fuel cancer cell development."
The researchers have not yet identified what specific signal or signals are inv
Source:University of California - San Francisco