506 THE CHEMISTRY OF TUMORS 



sue autolyzes somewhat more rapidly than corresponding normal tis- 

 sues," and, according to Neuberg, Blumenthal and others,^'* that cancer 

 extracts digest other tissues than themselves (heterolysis), a property 

 not exhibited by extracts of normal tissues. Miiller and others would 

 ascribe this heterolysis to the leucocytes present in the tumors. Nu- 

 cleases have been found in tumors as in other tissues," and in general 

 the enzymes which deamidize adenine and guanine (adenase and gua- 

 nase) are usually present if the original tissue possessed these enzymes 

 but no instance of the presence of xanthine oxidase or uricolytic en- 

 zyme has been obtained (Wells and Long, loc cit^'^). 



Hamburger finds that the enzymes of cancer tissue upon which the 

 glycyl-tryptophane and other enzyme tests for cancer are based, are 

 ereptases, resembling in all their properties the ereptases of normal 

 tissues, and not present in particularly large amount. However, Ab- 

 derhalden^^ has found evidence that certain peptids may be split in a 

 different way by cancer than by normal tissues, supporting those who 

 hold that cancer enzymes are different from normal tissue enzymes. 

 Autolysis of tumors is said to be augmented by x-ray, and especially 

 by radium (Neuberg), and tumor tissue is readily digested by trypsin. 



The presence of ereptases in carcinomatous gastric juice has been 

 especially studied because of its diagnostic possibilities, and the care- 

 ful investigation of Jacques and Woodyatt''^ seems to show conclu- 

 sively that such an enzyme is rarely present in gastric juice except 

 when derived from a cancer present in the wall of the stomach, pro- 

 vided peptolytic bacteria are excluded by filtration. Deaminizing 

 enzymes may also be found in gastric cancer secretions.''^ In the blood 

 of cancer patients there is usually an increased antitryptic activity, 

 ascribable to the reaction against enzymes absorbed from the cancer; 

 it is less pronounced with sarcoma.''^ The body tissues of patients 

 dying with cancer show a low ereptic activity, but the same occurs in 

 persons dying from other wasting diseases (Col well). ^^ This is also 

 true of other tissue enzymes; — at least purine oxidizing enzymes are 

 deficient in the liver tissue between secondary cancers (Wells and 

 Long''-) and the catalase is also reduced in liver tumors (Blumenthal 

 and Brahn)^^ and in the blood of tumor mice (Rosenthal);'^- in human 

 blood the catalase may vary either side of normal.*^* Brahn'^'* reports 



'« See Yoshimoto, Biochem. Zeit., 1909 (22), 299; Daels and Delenz6, Bull. 

 Acad. Med. Belg., 1913 (26), 833. 



'^ Bibliography by Hamburger, Jour. Amer. Med. Assoc, 1912 (59), 847. 



'5 Goodman, Jour. Exp. Med., 1912 (15), 477. 



'« Zeit. Krebsforsch., 1910 (9), 266. 



" Arch. Int. Med., 1912 (10), 560. 



'» Halpern, Mitt. Grenz. Med. Chir., 1915 (28), 709. 



'» Citronblatt, Med. Klin., 1912 (8), 138. 



80 Arch. Middlesex Hosp., 1909 (15), 96. 



*' Zeit. f. Krebsforsch., 1910 (8), 436. See also Weidenfeld, Wien. klin. Woc-h., 

 1918 (31), 324. 



82 Deut. med. Woch., 1912 (38), 2270. 



8' Rohdenburg, N. Y. Med. Jour., 1913 (97), 824. 



»*Zeit. Krebsforsch., 1917 (16), 112. 



