CHAPTER XVII 

 THE CHEMISTRY OF TUMORS ' 



Chemical investigations of tumors have been relatively few in num- 

 ber, but, so far as they have yet been made, there has been detected 

 little that indicates any important deviation of the chemical processes 

 of tumors from those of normal cells of similar origin. Likewise, the 

 chemical composition of tumor tissue resembles closely, on the whole, 

 the composition of related normal tissues. It is hardly to be im- 

 agined that the course of chemical changes is greatly different in 

 tumor cells from that in normal cells, in view of the abundant evi- 

 dence that the metabolic products of tumor cells are identical with 

 those of the cells from which they arose. Thus, metastatic growths 

 of thyroid tissue will produce thyroiodin in any part of the body, liver 

 carcinoma metastases produce bile, tumors from the choroid or from 

 pigmented moles produce melanin, etc." The capacity of tumor cells 

 to produce complicated products of metabolic action specific for the 

 parent cells from which they arose, as illustrated above, indicates 

 bej^ond question that the coui*se of their chemical activities is very 

 much like that of normal cells. So, too, the composition of the cells 

 is found to be similar indeed to that of the parent cells, both in re- 

 gard to primary and secondarj^ constituents. Thus, Bang found that 

 sarcomas derived from lymph-glands contain the particular nucleo- 

 proteins that are found normally only in lymph-glands, h^q^erne- 

 phromas contain much fat, lecithin, and cholesterol : squamous cell 

 carcinomas develop great amounts of kerato-hyalin ; carcinomas of 

 mucous membranes may contain much mucin, etc. 



Many have sought in cancer tissues a poison that might account for 

 the cachexia characteristic of new-growths. Extracts have been ob- 

 tained that were destructive to red corpuscles (hemolytic), and that 

 were sometimes slightly toxic to animals, but the results have not 

 seemed sufficiently striking to account for the appearance of cachexia. 

 Because of the interference with circulation, brought about in tumors 

 by pressure of the growing tissues upon their blood-vessels, areas of 

 necrosis frequently develop, and these, undergoing autolysis, yield sub- 

 stances that are hemolytic and toxic. "Whether these are the cause of 

 cancer cachexia, however, may be questioned ; but they are sufficient to 

 account for most of the experimental results as yet obtained. No sub- 



1 Literature given bv Xeuberp, Zeit. Krel)sforscli.. 1910 (10). 55; and Bhuiion- 

 thal, Ergebnisse Physiol., 1910 (10), 3(5.3. 



2 See Wells and Long, Zeit. Krebsforsch., 1013 (12), 598. 



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