Diet may influence the spread of a deadly type of breast cancer, study finds. A single protein building block commonly found in food may hold a key to preventing the spread of an often-deadly type of breast cancer, according to a new multicenter study. Investigators found that by limiting an amino acid called asparagine in laboratory mice with triple-negative breast cancer, they could dramatically reduce the ability of the cancer to travel to distant sites in the body. Among other techniques, the team used dietary restrictions to limit asparagine. Source 9s.