We have demonstrated that GLUT1 is the most highly expressed hexose transporter in ErbB2- and PyVMT-induced mouse mammary carcinoma models, and that reducing the level of GLUT1 using shRNA or Cre/lox results in reduced glucose usage, reduced growth on plastic and in soft agar, and impaired tumor growth in nude mice. This evidence concerns the gene ERBB2 and neoplasm.