Since cross-talk exists between p53 and Hif1 [31], it is plausible that a metabolic shift towards increased glycolysis or reductive glutamine metabolism may be a common underlying mechanism for augmented tumor growth with exercise in the p53+/-MMTV-Wnt-1 and the C3(1)SV40Tag-p16-luc. This evidence concerns the gene HIF1A and neoplasm.