In early studies on energy metabolism of tumor cells, it was proposed that the enhanced glycolysis was induced by a decreased oxidative phosphoryla-tion. Since then it has been indiscriminately applied to all types of tumor cells that the ATP supply is mainly or only provided by glycolysis, without an appropriate experimental evaluation.

Many tumor types exhibit an impaired Pasteur effect, i.e. despite the pres-ence of oxygen, glucose is consumed at an extraordinarily high rate com-pared with the tissue from which they originate – the so-called ‘Warburg effect’.