CYTOCHEMICAL STUDY 



OF ESTERASE ACTIVITY 



OF HUMAN NEOPLASMS 



AND STROMAL MACROPHAGES 



B. MONIS and T. WEINBERG 



Department of Pathology, Sinai Hospital, Baltimore, Maryland 



This report deals with a cytochemical study of esterase activity of 

 human neoplastic cells and of stromal macrophages. The esterase 

 activity of turaor cells was found to be frequently high. Malignant 

 epithelial cells stained usually intensely, whereas sarcomas and allied 

 processes showed low or no activity. The product of esterase activity 

 appeared located in some cell membranes and in granular or spheroidal 

 bodies showing in some cases particular intracellular distribution, 

 though no definite organelle structures could be identified. Macrophages 

 showed various degrees of reaction, highest esterase activity being 

 shown in the mature macrophage which contains metabolic products 

 such as hemosiderin. Because of the content of esterase it is suggested 

 that various stages of macrophage development could be traced and 

 indirect évidence obtained of disintegration of macrophage in situ. 

 Studies with various chemicals with inhibitory effect on esterases 

 suggest that esterases shown in this study are of the non-specific 

 type (aliesterases). A comparison of various naphthol esters of acetic 

 acid (« naphthyl acétate, j8 naphtyl acétate and naphthol AS acétate) 

 and 5 Bromoindoxyl acétate indicates the resemblance of results when 

 différent methods are used. 



Sixty-two malignant and eleven benign tumors were studied. Formalin- 

 fixed tissue, frozen sections and naphthol AS acétate and diazotized 

 4-o-tolylazo-o-toluidine (Fast Garnet Sait GBC new) was the main 

 procédure used in this study. 



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