HISTOCHEMISTRY OF ENZYMES IN TUMOURS 

 AND ITS SIGNIFICANCE IN PATHOLOGY 



R. G. J. WILLIGHAGEN 



Section for Applied Histochemistry, 

 Laboratory of Pathology, University of Leiden, Netherlands 



Expériences with methods for demonstrating enzymes in tissue sections 

 applied on frozen sections of unfixed human tumour spécimens are re- 

 ported. At the présent time in about 700 tumour spécimens the activity of 

 the hydrolytic enzymes alkaline and acid phosphatase bas been investi- 

 gated. In 350 of thèse spécimens the activity and the localization of 

 5-nucIeotidase, adenosine-tri-phosphatase, non-specific esterase and 

 aminopeptidase has also been studied. On about 150 tumours methods for 

 5 différent dehydrogenases were also applied. 



Enzyme activities for each spécifie enzyme are found to be distributed 

 among tumour cells of différent types in a spécifie pattem. This enzyme 

 pattem can be correlated with the type of tumour as well as in some cases 

 with its grade of differentiation. Several tumours can be characterized by 

 the activity of one or more enzymes. When using ail the hydrolytic enzymes 

 mentioned above, it is possible to characterize many human tumours on 

 their enzyme pattems. Metastasis in gênerai were found to possess the 

 same enzyme pattem as the primary tumour. 



Some examples of the results of the systematic application of histo- 

 chemical enzyme methods in pathology will be discussed. 



1) In the differential diagnosis of adenocarcinoma of the lung from other 

 adenocarcinomas on the basis of the activity of alkaline phosphatase and 

 aminopeptidase in their cells. 



2) The use of aminopeptidase in the diagnosis of gastric carcinoma, 



3) In the differential diagnosis of reticulumcellsarcoma and anaplastic 

 carcinoma on the activity of acid phosphatase, non-specific esterase and 

 adenosine-tri-phosphatase. 



Enzyme methods were found useful as a criterion for tumour cell differ- 

 entiation. Examples: 



1) Decrease of acid phosphatase activity in anaplastic carcinoma of the 

 colon, compared with well differentiated adenocarcinoma of this organ. 



2) The alkaline phosphatase activity as an indication for the grade of 

 differentiation of tumours of the connective tissue. 



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