The substances may help cancer cells in other ways, too. Previous research has suggested that glutathione affects the activity of a protein called RhoA, which helps cells move to different parts of the body. “If you were to select one protein that is known to be involved in [cell] migration, RhoA is it,” Bergö explains. He and his colleagues confirmed that the extra glutathione in the treated mice caused levels of RhoA to increase in their metastatic tumors. In their 2014 lung cancer study they also found that antioxidant supplements caused lung tumor cells to turn off the activity of a well-known cancer-suppressing gene called ; its inactivation is believed to drive metastasis. And Schafer’s work has shown that antioxidants help migrating breast cancer cells survive when they detach from the extracellular matrix, the network of proteins surrounding cells.