The binding of peroxidase-labelled lectins to human breast epithelium. II--The reactivity of breast carcinomas to wheat germ agglutinin.

The binding of peroxidase-labelled wheat germ agglutinin (WGA) to a series of 125 human breast carcinomas has been studied. Routine fixation and processing has been shown to have no deleterious effect on reactivity. In contrast to the homogeneous binding of WGA to normal and hyperplastic human breast previously reported, the binding of WGA to breast carcinomas exhibits heterogeneity. This is of two forms: (1) in relation to cell reactivity, which is significantly correlated to tumour differentiation, with fewer cells reacting in those carcinomas showing loss of histological differentiation; (2) with regard to the interaction between WGA and specific saccharides of cellular glycan-components, binding to sialic acid appearing to be of significance to varying degrees in some carcinomas but not in others nor, as previously reported, in normal breast. The alteration in WGA-saccharide interaction is an indicator of the heterogeneity of the carbohydrate chains of glycoproteins within neoplastic cells of the same tumour and between carcinomas. The other finding of note has been that of the significant association between heterogeneity of cellular reactivity to WGA and the presence of axillary lymph node metastasis, but a lack of correlation between virtual absence of reactivity and nodal metastasis.