The distribution of lectin receptor sites in human breast lesions

The lectin-binding sites for peanut agglutinin in invasive breast ductal carcinomas and their metastasis

Peanut agglutinin (PNA) lectin-binding site patterns in primary invasive breast ductal not otherwise specified (NOS) carcinomas are related to aggressiveness of the tumor. The present study was designed to compare the expression of PNA-binding sites in the primary tumor and in local lymph node metastases. The expression of lectin-binding sites was studied using the avidin-biotin complex/immunoperoxidase technique and analyzed in relation to age of the patient and size of the breast cancer. Breast cancers and their metastases showed negativity or positivity, the latter being divided into "apical" and "non-apical" (i.e. membrane and/or cytoplasmic) depending on the main localization of staining in tumor cells. No correlation was found between primary tumors and metastases as regards PNA-binding patterns, which confirms the opinion that advanced primary tumors are polyclonal and that selected subclones of malignant cells give rise to metastases. Furthermore, the fact that primary tumors with PNA non-apical expression, a feature related to aggressiveness and poor differentiation, may have lymph node metastases with apical expression, suggests that this pattern, although no longer evident in the primary tumor, is involved in the process of cell metastasis.

Binding evaluation of Isoform 1 from Cratylia mollis lectin to human mammary tissues

The phenomenon of altered carbohydrates in transformed cell surfaces has been studied through histochemical techniques using lectins. Specific binding patterns to normal and transformed mammary tissues were evaluated by Isoform 1 from Cratylia mollis lectin (Cra Iso 1). Protocols using a direct method, incubation of Cra Iso I conjugated to peroxidase (Cra Iso 1-Per) with mammary tissues, followed by diaminobenzidine and hydrogen peroxidase interaction, were performed. Neoplastic tissues, marked by Cra Iso 1, showed a higher intensity of staining than normal ones, in comparison with Canavalia ensiformis lectin, Concanavalin A (Con A), conjugated to peroxidase (Con A-Per). The assay with Cra Iso 1 also indicated a possible utilization of this lectin to characterize normal and transformed mammary cells.

The lectin-binding sites for peanut agglutinin in invasive breast ductal carcinomas and their role as a prognostic factor

The present study was designed to analyze the expression of lectin-binding sites for peanut agglutinin (PNA) in paraffin sections of primary invasive ductal carcinoma not otherwise specified and to consider PNA lectin histochemistry as a further aid in the prognostic evaluation of breast cancer. The expression of lectin-binding sites was studied using the avidin-biotin complex/ immunoperoxidase technique, and analyzed in relation to the different clinical, pathological, and biological parameters of the primary disease, i.e. the presence or absence of nodal metastases, pre- or post-menopausal age, size of the tumor, mitotic activity index, morphometric prognostic index, DNA content, S-phase fraction, and steroid receptor status. The results show significant differences in PNA binding patterns among malignant epithelial breast cells. There was no expression of PNA-binding sites in 14 out of 157 tumors, while 64 showed mostly apical (membrane) staining and 124 non-apical (membrane and/or cytoplasmic) staining. Apical staining was mostly observed in patients without lymph node metastasis, with positive steroid receptor status, and those who were postmenopausal diagnosis; non-apical staining was mostly observed in lymph-node-positive premenopausal patients negative for steroid receptors and with aneuploid tumor cells. Our results indicate that, in malignant breast cells, there is an alteration of cell-surface glycoconjugates, shown by heterogeneity within a histopathologically defined group, which is related to different properties of tumor cells. The apical PNA binding pattern indicates a better differentiation of tumor cells while non-apical PNA binding suggests a higher metastatic potential. Specific PNA lectin binding patterns should be considered as a further reliable prognostic factor in breast cancer.

Localization of endogenous beta-galactoside-specific lectins by neoglycoproteins, lectin-binding tissue glycoproteins and antibodies and of accessible lectin-specific ligands by mammalian lectin in human breast carcinomas

Protein-carbohydrate interactions constitute a system of molecular interaction with relevance to pathologic conditions. Carrier-immobilized carbohydrate structures enable the histochemical investigation of the protein part of this recognitive system. However, thorough systematic studies are inevitably required for standardized application of this relatively novel class of markers. Consequently, serial sections of 21 cases of malignant breast lesion were comparatively analyzed with three different types of probe, specific for beta-galactoside-binding lectins. In addition to the chemically lactosylated neoglycoprotein, human lectin-binding glycoproteins, purified by affinity chromatography on resins with an immobilized beta-galactoside-specific lectin, and a lectin-specific antibody were employed to answer the question whether differences occur in their capacity for lectin localization. The patterns of staining were qualitatively similar, the lectin-binding glycoproteins yielding the most intense reaction. Having assured the reliable applicability of the neoglycoprotein, structural alterations of the subterminal carbohydrate residue on the labelled carrier addressed the issue, whether selectivity of binding can be inferred histochemically, allowing rational synthetic tailoring. An N-acetylglucosamine residue in beta-1,3-linkage proved to be a less favorable extension than this type of sugar in beta-1,4-linkage or an N-acetylgalactosamine moiety in beta-1,3-linkage. Binding was clearly reduced in cells of normal breast tissue with this probe. In order to gain evidence on the expression of potential carbohydrate ligands for the glyco- and immunohistochemically localized binding activity, a labelled mammalian beta-galactoside-specific lectin was similarly used as histochemical tool. It effectively bound to accessible sites in the sections. The binding pattern was different to that of plant lectins with specificity to beta-galactosides. This result underscores that caution is necessary in the functional interpretation of results of studies with plant, not mammalian lectins.(ABSTRACT TRUNCATED AT 250 WORDS)