Glucose enters cells through various transporters including the GLUT family of facilitative transporters, the sodium/glucose co-transporters, and the recently discovered SWEET family. however, only the role of the GLUT family has been extensively studied in cancer cells. There are 14 GLUT proteins in the human and 12 in the mouse. GLUT1, encoded by SLC2A1, is the predominant transporter overexpressed in tumors, including hepatic, pancreatic, esophageal, brain, renal, lung, cutaneous, colorectal, endometrial, ovarian, cervical, and breast, as well as head and neck tumors.