426 THE CHEMISTRY OF TUMORS 



benign tumors. The composition varies greatly with the origin, 

 although to a less extent than with the benign tumors. As 

 Bang and Beebe have shown, the tumors arising from lymphatic 

 tissues show the chemical characteristics of these structures, and 

 contain histon nucleinate. Tumors from squamous epithelium 

 develop keratin in direct proportion to the amount of maturity 

 the cells reach. Even the most complex and specific products 

 of metabolic activity may be developed by malignant tumors 

 (e. g.j thyroiodin, adrenalin, bile), and in a form and condition 

 capable of performing function. As Buxton has shown, malig- 

 nant tumors produce a great variety of intracellular enzymes. 

 The idea that glycogen is present in tumors in proportion to 

 their malignancy has been disproved by Lubarsch, Gierke, and 

 others ; among the malignant tumors glycogen is found particu- 

 larly in chorioepitheliomas, hypernephromas, and squamous cell 

 carcinomas. Of particular importance is the observation of 

 Beebe, that the composition of metastatic growths is modified 

 by the organ in which they are growing, so that they tend to 

 resemble the organ serving as their host. 



As to the special varieties of malignant growths, there is little 

 as yet determined concerning their chemistry beyond what has 

 been stated above. Their variations in composition are largely 

 the direct result either of their resemblance to some normal 

 tissue or of degenerative changes that they have undergone. 



" Colloid " carcinoma may be mentioned specially, in view 

 of the confusion caused by the lax use of the term " colloid " 

 (q. v., p. 354). The fluid contents of colloid cancers of the 

 gastro-intestinal tract are usually chiefly epithelial mucus, con- 

 taining mucin mixed with a greater or less quantity of proteids 

 from degenerated cells and serous effusion. This mucin is acid 

 in reaction, is precipitated by acetic acid, and has an affinity for 

 basic dyes. The colloid cancers of the mammary gland, in which 

 the " colloid degeneration " involves the stroma, probably contain 

 a connective-tissue mucin, analogous to that of the umbilical cord, 

 as also do the myxosarcomas, if we may judge by their origin 

 and staining reactions, but no exact chemical study of these 

 substances can be found. Colloid cancers of the ovary, arising 

 usually from the same structures as the ovarian cysts, contain 

 pseudomucin or allied bodies (see " Ovarian Cysts "). Colloid 

 tumors of thyroid tissue contain the typical colloid of normal 

 thyroid tissue, even when metastatic in other organs ; in the 

 tumor colloid is a relatively normal proportion of iodin 

 (Gierke 1 ). 



1 Hofmeister's Beitr., 1902 (3), 286. 



