The histochemistry of glycosidases in human benign and malignant breast tissue

Histochemical methods for the localization of four glycosidases (beta-glucuronidase, beta-N-acetyl glucosaminidase, beta-D-galactosidase and alpha-mannosidase) have been applied to 40 cases of human normal and hyperplastic breast tissue and 100 human breast carcinomas. All tissues have been fixed in formol-calcium at 4 degrees C and washed in gum sucrose. beta-Glucuronidase and beta-N-acetyl glucosaminidase have consistently been detected in essentially all cells of normal and hyperplastic tissue. A similar distribution has been found for better differentiated carcinomas but the number of cells with detectable enzyme decreases in the more poorly differentiated tumour. beta-D-Galactosidase and alpha-mannosidase have only been demonstrated in very occasional cells in normal breast tissue. The incidence increases in hyperplastic tissue, and in approximately half the carcinomas many cells have detectable enzyme. The localization of beta-D-galactosidase has not been related to tumour differentiation but the better differentiated carcinomas tend to have few cells with demonstrable alpha-mannosidase. Although it has been suggested that glycosidases can have an effect on membrane function no differences have been found between those carcinomas having a few or many cells with detectable enzyme and the presence or absence of axillary lymph node metastasis. Total enzyme activity cannot be detected in fixed tissue, nor can an accurate quantitative assessment be made, but under the conditions of this study it is possible to conclude that there are differences between normal and malignant breast tissue in the localization of glycosidases.