Previously, we proposed a new model for understanding the Warburg effect in tumorigenesis and metastasis. In this model, the stromal fibroblasts would undergo aerobic glycolysis (a.k.a., the Warburg effect)--producing and secreting increased pyruvate/lactate that could then be used by adjacent epithelial cancer cells as "fuel" for the mitochondrial TCA cycle, oxidative phosphorylation, and ATP production.