Cancer rewires the metabolism of tumor cells, converting them into lean, mean, replicating machines. But like Olympic athletes who rely on special diets to perform, tumor cells’ amped-up metabolism can also make them dependent on specific nutrients for survival. For years, scientists have been trying to identify and understand these cellular cravings in hopes of creating new cancer treatments that work by blocking off access to necessary nutrients and starving tumors to death. In a new study, Duke University scientists report that cells from a vicious and treatment-resistant form of breast cancer, called triple negative breast cancer (TNBC), die off rapidly when deprived of a key nutrient called cystine. By examining the cause of cell death, they found that this “cystine addiction” is triggered by a mechanism that many kinds of tumor cells use to break away and migrate to new locations in the body. “This process is well-known and shows up in metastatic cancer cells, and what we found is that it also makes the cells cystine-addicted,” said Jen-Tsan Ashley Chi, associate professor of molecular genetics and microbiology at the Duke University School of Medicine and senior author on the study. “This is great news, because these are the cells that we really want to get rid of.”?