Discussion on Tumor Respiration 



C. A. BAUMANN, University of Wisconsin, Chairman 



CHARACTERISTICS OF TUMOR RESPIRATION 



K. A. C. ELLIOTT 

 Institute of the Pennsylvania Hospital, Philadelphia 



Having been out of the cancer research field for some time, I am 

 not in a position to discuss many recent developments. But it may 

 be useful to start this discussion with a resume of the generahzations 

 and theories concerning the metabolism of cancer tissue that have 

 been proposed from time to time. My remarks may appear somewhat 

 pessimistic, for it does not seem to me that any definite and peculiar 

 characteristic of tumor metabolism has been proved. However, later 

 speakers who are familiar with more modern work will perhaps 

 strike a more optimistic note. 



Warburg's First Theory.— As is well known, Warburg and his 

 school discovered that, whereas slices of a number of normal tissues 

 produce lactic acid from glucose or glycogen rapidly in the absence 

 of oxygen (anaerobic glycolysis), cancer tissue slices show an un- 

 usual ability to continue production of lactic acid from glucose in 

 the presence of oxygen (aerobic glycolysis). In his early studies 

 Warburg happened to study tumors which showed very low oxygen 

 uptake rates. He therefore concluded that in cancer tissue the 

 respiratory mechanism was impaired and that glycolysis took its 

 place as a means for producing energy. Later, however, Warburg 

 observed, and emphasized, the fact that the oxygen uptake rate of 

 most tumor tissues under good conditions is not usually lower than 

 that of many normal tissues. 



Warburg's Second Theory.— Warburg concluded that since the 

 respiration rate of cancer tissue might be normal while rapid aerobic 

 glycolysis continued, there must be something wrong with the 

 type of respiration in the tumors. Some sort of damage to the respira- 

 tory mechanism must have occurred in the production of tumor cells 

 which caused a loss of eflBciency of respiration in suppressing gly- 

 colysis. High anaerobic glycolysis appeared to be a general property 

 of growing or multiplying tissues, since it was found in embryo tissue 

 and testis, but in these normal tissues glycolysis was largely abolished 

 when respiration occurred, that is, in the presence of oxygen. In 



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