The development of GLUT inhibitors for the treatment of cancer has further gained momentum by the observation that ritonavir, which has originally been developed as an inhibitor of HIV protease, coincidentally inhibits the members 1 and 4 (Murata et al., 2000; Hertel et al., 2004; Vyas et al., 2010) of the GLUT family. This evidence concerns the gene SLC2A1 and cancer.