Approximately every 13 minutes, in the United States alone, one woman will die of breast cancer. Metastasis, the main cause of patient death, is the process by which breast cancer cells spread throughout the body by means of blood and lymphatic vessels. Breast cancer cells metastasize primarily via the lymphatic vasculature, which is lined by endothelial cells. Previous research suggests that lymphatic endothelial cells (LECs) help tumors grow more quickly, but there is little information on whether, or how, the metabolism of breast cancer cells is impacted by the LECs. Unlike normal cell metabolism, which relies on oxidative phosphorylation, breast cancer cell metabolism relies on glycolysis and therefore consumes more glucose.