Weinberg and his colleagues used a mouse model of breast cancer to explore the impact of wound healing on cancer metastasis. They found that in mice with a transplanted breast cancer tumor, natural immune-system defenses, such as T cells, kept the tumor cells in a dormant state in which they did not divide or spread. In mice with a transplanted breast cancer tumor that were healing from an induced injury, however, the tumors metastasized at a much higher rate.
The findings suggest that inflammation that develops during the wound-healing process interferes with the immune system, preventing it from keeping tumor cells dormant and inactive.
“What we propose is that some of these disseminated cells are kept under control by the immune system,” Weinberg says. “What we find is, in a model of postsurgical wound-healing, it’s not the surgery itself but the subsequent wound-healing response that can act throughout the body to suppress certain kinds of immunological functions. When these immunological functions are suppressed, these
disseminated cancer cells that had been under control can sally forth and generate.”
“It’s a very important paper,” says Michael Retsky, PhD, a research associate at the Harvard T.H. Chan School of Public Health who has studied breast cancer surgery and relapse. “Surgeons have claimed for a very long time that surgery doesn’t cause cancer to spread. The simple answer is that it does. While cancer is a cellular disease, we are finding that most distant relapses in breast and probably other cancers result from systemic inflammation.”