II CARBOHYDRATES AND LIPIDS Ob I 



The significance of the hpid content or concentration upon the origin or growth 

 of mahgnant tissue is not apparent at this time. Perhaps more extensive quahta- 

 tive studies on the fatty acid composition and the steroid composition or the phos- 

 phohpids of larger number of tumors of varying types may reveal some importance 

 of these structures in the malignant processes. Medes et al. (1953) have found that 

 neoplastic tissues cannot synthesize sufficient fatty acids to meet the lipid needs 

 of the rapidly growing tissue. This aspect will be considered in further detail in 

 a following section. 



The interesting observation has been made by Kandutsch and Baumann (1954) 

 that administration of carcinogenic hydrocarbons greatly reduces the concentra- 

 tion of A^-cholestenol in mouse skin. The concentration of this sterol in a series 

 of tumors was essentially the same as that in most normal tissues. It would appear 

 that sterol metabolism may be involved in the process of cancer induction, how- 

 ever there are not sufficient data to define a sterol pattern that may be associated 

 with the growth or maintenance of the malignant cell. Lipoids in serum were 

 administered by Rondoni (1954) into tumor bearing animals; the growth of the 

 tumor was subsequently impeded which was attributed to antibody formation. 

 Rondoni also found a sulphophospholipid on both human and experimental tumors. 



The Rous fowl sarcoma is rich in hyaluronic acid (Harris et al., 1954). This 

 hyaluronate was similar to the hyaluronic acids of normal mammalian tissues. 

 Certain polysaccharides of bacterial origin possess considerable tumor necrotizing 

 activity (See Greenstein, Chapter viii, 1954). Takashi et al., (1954) have reported 

 that polysaccharide fractions, extracted, from ascites carcinoma, placenta, Yoshi- 

 da sarcoma or beef liver, exert an inhibitory action on cell mitosis. 



[b) Respiration and glycolysis 



The observations made by Warburg and associates almost 30 years ago still 

 retain the greatest importance in the search for a specific metabolic pattern for 

 malignant tissues. These investigators established that the cancer cell has the 

 capacity to jyoduce large^uan^tities^onactic a^idjrom^ 



ity was not lost in the presence o f oxygen . In order to reemphasize the importance 

 of ^Heseiasting observations the following quotation has been taken from the 

 translation of Warburgs' collected papers on tvimor metabolism. "Whilst, how- 

 ever, normal cells die if they glycolyse aerobically, the glycolysing tumor cell not 

 only continues to exist, but is even able to grow to an unlimited extent, turning 

 to account the chemical energy of the glycolysis. The aerobic glycolysis of the 

 tumour cell is derived in any case from a disturbance of the respiration. As a rule, 

 the respiration of the tumour cell is small, but in recent years tumour cells with 

 a large respiration have also been found" (Warburg, 1930). Currently there is a 

 considerable difference of opinion amongst some of our foremost scientists as to 

 the interpretation of the above W'arburg observations. Certainly this area of 

 cancer investigation is of the greatest importance and merits considerable atten- 

 tion. Accordingly, an attempt will be made to thoroughly review all findings to 

 present the views of the qualified participants in this controversy. 



Most of Warburg's original as well as subsequent findings reveal a high aerobic 

 and anaerobic glycolysis that is characteristic of cancer cells. The respiration 



Literature p. 919 



