It is well documented that the KRAS oncogene efficiently transforms non-malignant cells,and there is some evidence for the role of mitochondria in this process.Now Peng Huang and colleagues show that K-Ras induction results early on in mitochondria assuming the phenotype consistent with the so-called Warburg effect,i.e.,increased glycolysis and attenuated oxidative phosphorylation.Thus the K-Ras protein capable of swift induction of phenotypic changes typical of cancer cells,yet these changes are reversible,and for cells to irreversibly reach their full malignant potential a much longer K-Ras expression is required,implicating mitochondria in the longer-term effects of the oncogene.