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

Lectins as versatile tools to explore cellular glycosylation

Lectins are naturally occurring carbohydrate-binding proteins that are ubiquitous in nature and highly selective for their, often incompletely characterised, binding partners. From their discovery in the late 1880s to the present day, they have provided a broad palette of versatile tools for exploring the glycosylation of cells and tissues and for uncovering the myriad functions of glycosylation in biological systems. The technique of lectin histochemistry, used to map the glycosylation of tissues, has been instrumental in revealing the changing profile of cellular glycosylation in development, health and disease. It has been especially enlightening in revealing fundamental alterations in cellular glycosylation that accompany cancer development and metastasis, and has facilitated the identification of glycosylated biomarkers that can predict prognosis and may have utility in development of early detection and screening, Moreover, it has led to insights into the functional role of glycosylation in healthy tissues and in the processes underlying disease. Recent advances in biotechnology mean that our understanding of the precise binding partners of lectins is improving and an ever-wider range of lectins are available, including recombinant human lectins and lectins with enhanced, engineered properties. Moreover, use of traditional histochemistry to support a broad range of cutting-edge technologies and the development of high throughout microarray platforms opens the way for ever more sophisticated mapping - and understanding - of the glycome.

Lectinhistochemical and cytometrical evaluation of the corpus luteum of the rat at the end of pregnancy

Most studies on the biochemistry and structure of the corpus luteum have focused on elucidating the processes of progesterone synthesis and release. In the present work, the histochemical composition of the corpus luteum of the rat was evaluated using lectinhistochemistry on rats at the end of pregnancy (days 18-23). We also analysed the morphology of the luteal cells, to characterize the changes attributable to regression in this organ. Seven biotinylated lectins were used (CON-A, WGA, DBA, SBA, PNA, RCA and UEA-I) following pre-set protocols (ABC method). The average diameter and area of the cells and their nuclei were measured. High reactivity of the luteal cells was observed with CON-A and a lower reactivity with WGA. The capillary endothelium gave positive reactivity with WGA and to a certain extent with SBA, PNA and RCA. Vesicular structures were intensely stained with DBA, and were more abundant in sections from animals with more advanced pregnancy, which could be attributable to cellular debris, on the basis of their morphologic characteristics. There were no significant differences among the cytometric variables analysed in comparisons of the values corresponding to the different days of gestation. These observations, together with previous research, suggest that, on the day of delivery, the corpus luteum of the rat is in the very early stages of structural regression, with no changes at the morphological level, but with changes at the molecular level.

Wheatgerm agglutinin-mediated toxicity in pancreatic cancer cells

Lectin binding specificities for carbohydrate allow phenotypic and functional characterization of membrane-associated glycoproteins expressed on cancer cells. This analysis examined wheatgerm agglutinin binding to pancreatic cancer cells in vitro and the resulting toxicity. Membrane preparations of nine human pancreatic carcinoma cell lines were studied for lectin binding using wheatgerm agglutinin (WGA), concanavalin A (ConA) and phytohaemagglutinin-L (PHA-L) in a lectin blot analysis. Cell proliferation in vitro was measured by thymidine incorporation in the absence or presence of lectins at various concentrations. Sialic acid binding lectins or succinyl-WGA (succWGA) served as controls. WGA toxicity was tested after swainsonine or neuraminidase pretreatment. Binding and uptake of fluorescein-labelled lectins was studied under fluorescence microscopy. All pancreatic cell lines displayed high WGA membrane binding, primarily to sialic acid residues. Other lectins were bound with weak to moderate intensity only. Lectin toxicity corresponded to membrane binding intensity, and was profound in case of WGA (ID50 at 2.5-5 microg ml(-1)). WGA exposure induced chromatin condensation, nuclear fragmentation and DNA release consistent with apoptosis. Important steps for WGA toxicity included binding to sialic acid on swainsonine-sensitive carbohydrate and lectin internalization. There was rapid cellular uptake and subsequent nuclear relocalization of WGA. In contradistinction to the other lectins studied, WGA proved highly toxic to human pancreatic carcinoma cells in vitro. WGA binding to sialic acid residues of N-linked carbohydrate, cellular uptake and subsequent affinity to N-acetyl glucosamine appear to be necessary steps. Further analysis of this mechanism of profound toxicity may provide insight relevant to the treatment of pancreatic cancer.

Lectin histochemical HPA-binding pattern of human breast and colon cancers is associated with metastases formation in severe combined immunodeficient mice

Metastasis formation is a major clinical problem in cancer treatment, and no significant progress in the treatment of metastatic spread has been made. This apparent lack of progress is partly caused by the absence of clinically relevant animal models of metastases. The binding of the lectin Helix pomatia agglutinin (HPA) has been associated with a poor prognosis in breast and colon cancer patients. HPA-positive and -negative human breast and colon cancer cell lines were transplanted into severe combined immunodeficient (SCID) mice. HPA-positive breast cancer cell lines (MCF-7 and T47D) metastasized in SCID mice, whereas the HPA-negative ones (BT20, HS578T and HBL100) did not. The HPA-positive colon cancer cell line HT29 metastasized, while the HPA-negative ones (COLO320DM, SW480 and SW620) did not. However, in two of eight SCID mice inoculated with the HPA-negative colon cancer cell line, CACO2 metastatic deposits were found. Despite this exception, HPA binding is a good indicator of the metastasis of human breast and colon cancer cells in SCID mice: 23 out of 26 HPA-positive cancers metastasized, as opposed to only two out of 38 HPA-negative cancers. This experimental model is well suited for investigating the functional role of carbohydrate residues recognized by HPA in breast and colon cancer metastasis.

Lectin histochemical study of cholangiocarcinoma arising from stone-bearing intrahepatic bile duct

With the purpose of studying changes in the expression of glycoconjugate structures in cholangiocarcinoma and the nonneoplastic epithelium of stone-bearing intrahepatic bile ducts, a panel of 12 biotinylated lectins were used on formalin-fixed, paraffin-embedded tissue sections from 13 patients who had undergone surgical resection of cholangiocarcinoma and on nonneoplastic stone-bearing intrahepatic bile ducts from 10 patients. Of the 13 patients with cholangiocarcinoma 10 had hepatolithiasis and 3 did not. Among the 12 lectins, only wheat germ agglutinin (WGA) stained the cholangiocarcinoma and nonneoplastic epithelium of the stone-bearing intrahepatic bile duct. All nonneoplastic epithelia of stone-bearing intrahepatic bile ducts were stained heavily and homogeneously by WGA, the GlcNAC-specific lectin. The high columnar epithelium of both intramural and extramural glands was stained in the supranuclear region, while the low columnar epithelium of serous acini was stained in the whole cytoplasm. cytoplasm. In the well-differentiated cholangiocarcinoma, the WGA weakly stained the neoplastic cells in the supranuclear region, while it stained the luminal cytoplasmic membrane heavily. In the poorly-differentiated cholangiocarcinoma, about 50% of cancer cells were stained with WGA. The carcinoma was moderately stained in the cytoplasm. Less reactivity and a lower percentage of cells stained with lectin were found in cholangiocarcinomas when compared to nonneoplastic epithelia. This led us to conclude that there is a dramatic decrease in lectin-binding carbohydrate structures associated with cholangiocarcinoma progression.

Lectin binding patterns in normal liver, chronic active hepatitis, liver cirrhosis, and hepatocellular carcinoma. An immunohistochemical and immunoelectron microscopic study

We studied the binding patterns of 14 lectins in human normal and cirrhotic liver (LC) tissues and hepatocellular carcinomas (HCC) using the ABC method. Lectins were divided into 4 groups according to their binding patterns in normal tissues: (A) PHA, MPA, LcH, RCA-I, and WGA, which bound to hepatocytes and all three types of sinusoidal cells; (B) BPA, GS-I, PNA, and SBA, which bound to Kupffer cells and endothelia of interlobular arteries and veins and bile duct epithelia in the portal tract, but not to hepatocytes; (C) UEA-I, which bound only to endothelia of interlobular arteries and veins and bile duct epithelia in the portal tract; (D) LBA, Lotus, LPA, and SJA, which showed no binding. Thus group B lectins may be useful markers of Kupffer cells. Only electron microscopic examination revealed the precise binding sites of lectins in sinusoidal cells and hepatocytes. Hepatocyte cell surface polarities demonstrated by lectin binding in LC and HCC were different from those in the normal liver. The binding pattern of PHA to LC hepatocytes changed from a membranous to both a membranous and a cytoplasmic pattern, and that of LcH to HCC cells changed to dot-like staining in the cytoplasm. These changes of polarities in LC and HCC might be caused by changes in the distribution of lectin-binding carbohydrates or by the altered glycosylation of glycoconjugates.

Comprehensive lectin histochemistry of normal and neoplastic human choroid plexus cells: alternation of lectin-binding patterns through neoplastic transformation

Lectin histochemistry of the normal and neoplastic human choroid plexus cells [six choroid plexus papillomas (CPPs) and three choroid plexus carcinomas (CPCs)] was performed using eight representative lectins to study the development of sugar chain structures and also to determine whether lectins were useful for a histopathological diagnosis of choroid plexus neoplasms (CPNs). The normal choroid plexus cells reacted with Ricinus communis (RCA-I). Canavalia ensiformis (Con A), Limax flavus (LFA) and Triticum vulgaris (WGA), while Arachis hypoaea (PNA) stained them only after the removal of sialic acid. Human fetal choroid plexus cells at 8 weeks gestation already showed the same lectin-binding patterns as adult ones. All CPNs were stained by RCA-I and Con A in a similar manner as the normal choroid plexus cells. Although seven CPNs were positive for LFA, two CPCs were not stained by LFA, which bound to sialic acid. Two LFA-positive CPPs were stained by PNA before the removal of sialic acid. Moreover, unlike the normal choroid plexus cells, Ulex europaeus-, Glycine maximus- and Dolichos biflorus-binding sites often appeared, and WGA-binding sites of three CPNs remained even after sialic acid removal. In conclusion, the glycosialylation in normal choroid plexus cells was completed during the early embryonic stage. The lectin-binding patterns of CPNs were heterogenous in each case. The alternation of the glycosialylation and/or acquisition of binding sites for some lectins was sometimes observed through a neoplastic transformation.

Assessment of milk fat globule membrane antibodies and lectins as markers of short-term prognosis in breast cancer

The milk fat globule membrane antibodies HMFG1, HMFG2, NCRC 11 and four of the Mam 6 series, and the lectins peanut agglutinin, wheat germ agglutinin, Concanavalin A, Lotus tetragonolobus and Ulex europaeus I have been applied to 115 stage I and II breast carcinomas (median follow up = 36 months) to assess their value as prognostic markers. Of the milk fat globule membrane antibodies only NCRC 11 staining showed a relationship to development of recurrent disease and overall survival, but this did not act as an independent indicator over and above that provided by histological grade. None of the lectins gave prognostic information, including those whose binding related to node status or grade. It is concluded that for short-term prognosis none of the markers can given independent prognostic information over and above that provided by histological evaluation.

Flow cytometric analysis of cell surface carbohydrates in metastatic human breast cancer

Helix pomatia agglutinin (HPA)- and Concanavalin A (Con A)-binding carbohydrate expression were studied on 32 tumour samples from primary adenocarcinoma of the breast and 12 samples from lymph node metastases. Live cells were spilled from each of the fresh samples and the extent of fluorescent-labelled HPA and Con A-binding was assessed by flow cytometry. The extent of brightness was expressed in a defined quantitative fashion and the percentage of positive cells was accurately determined from a sample of 10,000 cells per tumour. Correlation of binding with clinicopathological features showed that HPA but not Con A related to lymph node involvement (P = 0.001) in tumours of higher grade (II and III). Spilled tumour cells (non-lymphocytes) were selected from the lymph nodes and the presence of HPA binding cells in the involved lymph nodes was found to relate to positive HPA binding in autologous primary tumours (P = 0.002). Dual-label analysis of HPA and Con A binding showed characteristic features for each tumour. The study demonstrates the use of flow cytometry as a simple and effective technique in detecting differences in lectin binding in live spilled cells from fresh breast cancer tissues. This method may prove to be particularly useful if performed preoperatively on cells in fine-needle aspirates.

The use of lectins in histopathology

Lectins are proteins and glycoproteins extracted predominantly from plants which have the capacity to bind sugars specifically. This property makes them of interest for histopathology since they will bind to saccharides forming parts of glycoproteins and glycolipids of tissue constituents. Lectins have and can be used as reagents for mucin histochemistry, to identify specific cells, in the recognition of glycoprotein alterations in disease states, in studies of infectious diseases, and in the assessment of glycoconjugate alterations occurring with malignancy. They can be used for both light microscopic and ultrastructural localisation and various methods are available. It is important though, to consider the nature of the glycoconjugates under study and select lectins appropriately because of their varying specificities and binding characteristics. A panel of lectins should be used to study a particular configuration. Care should be taken with tissue fixation and processing. It must be remembered that an open and critical mind should be kept concerning interpretation of results. At the present time lectins have a limited value diagnostically, but the binding of Ulex europeus agglutinin to endothelium is certainly of value.

Studies of lectin binding to the human cervix uteri: II. Cervical intraepithelial neoplasia and invasive squamous carcinoma

The cell surface carbohydrate profile of formalin-fixed paraffin-embedded tissue sections of neoplastic cervical squamous epithelium was evaluated using lectins of Bauhinia purpurea (BPA), Canavalin ensiformis (Con A), Griffonia simplicifolia I (GS I), Griffonia simplicifolia II (GS II), Maclura pomifera (MPA), Archis hypogaea (PNA), Glycine max (SBA), Ulex europaeus I (UEA I) and Triticum vulgaris (WGA). Three lectins (BPA, Con A and PNA) showed a similar pattern of staining in both normal squamous epithelium and in cervical intraepithelial neoplasia (CIN). Variable alterations were seen in lectin-binding patterns in CIN with seven lectins (GS I, GS II, MPA, PNA, SBA, UEA I and WGA). A significant difference was seen between the intensity of staining of normal squamous epithelium and CIN with all lectins except WGA. The alteration in GS II-binding pattern and intensity was significantly related to grade of CIN. No correlation was found between lectin binding and the presence of koilocytes in squamous epithelium. Cases of invasive squamous carcinoma showed a heterogeneous lectin-binding pattern and no significant association was found between lectin binding and tumour differentiation of patient survival. These results indicate that neoplasia in cervical squamous epithelium is associated with alterations in terminal alpha-Man residues, alpha- and beta-GalNAc residues, alpha- and beta-GlcNAc residues, alpha- and beta-Gal residues, and alpha-Fuc-containing residues, present in the outer parts of both N-linked and O-linked glycoconjugates. The implications of these findings are discussed.

Lectinohistochemistry of human bladder cancer: loss of lectin binding structures in invasive carcinomas

With the purpose of studying changes in the expression of glycoconjugate structures in urothelium, nine different lectins (PNA, WGA, VFA, GSA II, STA, UEA I, LCA, DBA and HPA) with specificity for mono- or oligo-saccharides were used on formalin-fixed, paraffin-embedded tissue sections from 47 patients who had undergone surgical resection for bladder tumors and on normal urothelial biopsies from 10 patients. The tumors were graded and a lectinohistochemical method using biotinylated lectins and avidin-biotin-peroxidase complex was used to demonstrate the lectin binding. Positive staining reactions of cells in cytoplasm and on membranes were evaluated in the basal, the intermediate, and the luminal cell layers, respectively. In both normal and atypical urothelium lectin binding predominated in the luminal cell layer and decreased towards the basal cell layer. In normal urothelium all lectins stained greater than 66% of the cells in the luminal cell layer in cytoplasm and between 5 and 100% of the cells on membranes depending on the lectin used. A gradual loss of lectin-binding structures was seen with increasing grade of atypia. The range of this decrease varied considerably from one lectin to another, but it was consistently found that the percentage of cells stained in cytoplasm and on membranes decreased. A significantly lower percentage of cells stained in cytoplasm was found in invasive tumor cell-islands compared to normal urothelium. In invasive tumor cell-islands staining of cells on membranes was completely absent, except for HPA lectin that stained less than 10% of the cells. In conclusion, we demonstrate a dramatic decrease in lectin-binding carbohydrate structures associated with urothelial malignant progression.

The binding of peroxidase-labelled lectins to human endometrium in normal cyclical endometrium and endometrial adenocarcinoma

The nature of endometrial glycoconjugates throughout the menstrual cycle was investigated using a panel of lectins directed against specific sugar groups. This approach was also applied to a series of endometrial adenocarcinomas the findings for which were compared with those of normal controls. A change in the expression of glycosubstances was found in relation to the phase of the menstrual cycle; that there was increasing sialylation of terminal galactose groups during the secretory phase. This change may be influenced by progesterone. One group of endometrial adenocarcinomas exhibited binding patterns similar to those seen in secretory endometrium and this may be related to progesterone receptor state. Expression of fucose containing glycosubstances was identified in half of the carcinomas but not in the normal control tissue, thus indicating that a change in fucosylation occurs with endometrial neoplasia. None of the lectin binding patterns, however, correlated with variables in the patients themselves or within the tumours.

Analysis of glycoproteins released from benign and malignant human breast: changes in size and fucosylation with malignancy

Radiolabelled glycoproteins released into media from benign and malignant human breast tissue after 48 h organ culture have been analysed using SDS polyacrylamide gel electrophoresis and fluorography. Major differences were identified between benign and malignant tissues: (i) a considerably higher incidence of glycoproteins in the molecular weight range 210-280 kDa detected from carcinomas than benign samples, with incidence being greater in poorly differentiated tumours; (ii) fucosylation of these glycoproteins released from carcinomas but not benign breast; (iii) heterogeneity, particularly of fucosylation, between the carcinomas but consistency amongst benign breast. A glycoprotein of MW 230 kDa was of particular interest since it was not detected from any benign samples but was present in 11 of 17 carcinomas, when it was almost always fucosylated. This could prove to be a useful tumour marker.

Lectin binding in the male breast

Twenty-four male breast lesions including ten normal, ten gynaecomastia, and four infiltrating carcinomas were studied for the presence and distribution of lectin binding carbohydrates. For comparison, tissue sections of five normal female breast lesions, ten each of fibrocystic disease, fibroadenoma, and carcinoma, were also included in this study. Formalin-fixed, paraffin-embedded tissues were tested with Glycine maximus (SBA), Dolichos biflorus (DBA), Triticum vulgaris (WGA), Concanavalia ensiformis (Con A), Lotus tetragonolobus (LTA), Arachis hypogaea (PNA), and Bandeiraea simplicifolia (BSAI). The lectin-binding patterns were similar in normal, gynaecomastia, and carcinoma, and were not pathognomonic to any male breast lesion. These lectin reactive patterns in the male breast appear to be similar to those reported for the female breast lesions.

The distribution of lectin receptor sites in human breast lesions

Conflicting data regarding the status of A, B, H and T antigens in epithelium of normal, mastopathies, fibroadenomas and carcinomas of the breast stimulated us to re-examine the carbohydrate residues in these condition. Currently, we extended the number of carbohydrate residues studied by using ten different biotinylated lectins as probes and avidin-biotin-peroxidase complex (ABC) as a visualant. In addition, the pattern of lectin staining of cancerous cells in primary and metastatic sites was compared. In primary and metastatic breast carcinomas, lectin receptor sites were stained more intensely with Concanavalia ensiformi agglutinin (*Con A), Ricinus communis agglutinin-I (RCA-I) and wheat germ agglutinin (WGA), than in normal breast, in mastopathies or in fibroadenomas. Cryptic receptor sites for peanut agglutinin (PNA) were stained in all cases of breast carcinomas, while free PNA sites stained only in a few cases of well-differentiated carcinomas. Receptors sites for Ulex europaeus agglutinin-I (UEA-I) stained non-malignant epithelium of patients with blood group H but did not stain malignant cells. The results show significant differences in lectin-binding patterns and staining intensities between normal and non-malignant, and malignant epithelial breast cells. Furthermore, these results indicate that in malignant cells, there is an increased content of sialic acid-rich carbohydrates but not of asialylated glycoconjugates.

Dual-parameter flow cytometry of transitional cell carcinomas. Quantitation of DNA content and binding of carbohydrate ligands in cellular subpopulations

Quantitative DNA measurements and estimates of blood group-related carbohydrate antigen expression have been used as predictive parameters in transitional cell carcinomas (Ca). To obtain an accurate quantitative characterization of cellular subpopulations on the basis of these parameters, the authors developed a dual-parameter flow cytometric method using a fluorescence-activated cell sorter. With this method single-cell suspensions from 26 transitional cell carcinomas were analyzed by means of propidium iodide (red fluorescence) as DNA ligand, and peanut agglutinin (PNA), wheat germ agglutinin (WGA), and anti-blood group A antibody (aBGA) as carbohydrate ligands. The latter ligands were visualized directly or indirectly by FITC (green fluorescence). The carbohydrate ligand binding was correlated to the DNA content of cell populations in the way that aneuploid populations showed a higher PNA binding (P less than 0.0002) and a lower WGA (P less than 0.01) and aBGA (P less than 0.04) binding than did diploid cell populations. The binding of PNA to aneuploid populations could be further increased (P less than 0.004) by neuraminidase treatments. Thus, aneuploid cells express both neuraminic acid substituted and unsubstituted PNA receptors. The carbohydrate ligand binding was cell cycle-dependent, as it was reduced (less than 0.008) in the G2-M phase. A low WGA (P less than 0.004) or aBGA (P less than 0.02) binding was correlated to tissue invasion. Immunohistochemistry with the carbohydrate ligands showed a good correlation between aBGA (P less than 0.0005) and PNA (P less than 0.004) binding to tumor cells and flow cytometric assay of these, as well as a correlation (P less than 0.003) between cellular location of WGA receptors and flow cytometric assay of these. It seems that dual-parameter flow cytometry represents an important tool in the characterization of bladder tumors.

Analysis of differentiation and transformation of cells by lectins

During differentiation cells are known to change their biological behavior according to their genotype. This is thought to be accompanied by a modulation of cell surface determinants expressed on the outer cell membrane. Vice versa, cell surface molecules are suggested to mediate extracellular signals to the genome. Most of these molecules integrated in the cell membrane have been proven to be glycoconjugates. The carbohydrate moieties of these molecules can be detected by means of lectins that are characterized by their ability to react specifically with distinct terminal sugar sequences. Thus, lectins have been used as appropriate tools for studying the modulation of functionally important membrane-associated molecules during the differentiation of cells, in particular of B- and T-lymphocytes. Moreover, lectins have been proven to distinguish between differentiated cells and malignant cell clones, according to the hypothesis that transformed cells possess a glycoconjugate profile that corresponds to the stage of differentiation at which they are arrested. Since lectins, like monoclonal antibodies, make it possible to study functionally important molecules that are associated with differentiation and malignancy, they might be of value for diagnostic purposes and, moreover, for analyzing malignant transformation.

Predictive value of lectin binding on breast-cancer recurrence and survival

A new approach for predicting long-term survival of breast-cancer patients is the detection of carbohydrate expression in paraffin-embedded sections of the primary tumour. The binding of a lectin (HPA), derived from the albumin gland of the Roman snail, Helix pomatia, to N-acetyl-galactosaminyl oligosaccharides appears valuable in assessing long-term prognosis. The clinical progress of 179 patients, followed-up for 15-20 years, was related to staining of paraffin sections of their primary breast cancers by HPA. All patients had had mastectomy but were not stratified by pathology or treatment. There were significant differences, in premenopausal patients, between groups with and without HPA staining in both time to first recurrence and survival time. HPA binding provides an extra tool for staging to aid decisions in early adjuvant treatment, with the advantage of being applicable to routinely fixed paraffin-embedded material.

Analyses of protein extracts of human breast cancers: changes in glycoprotein content linked to the malignant phenotype

The protein and glycoprotein composition of Triton X-100 extracts of breast biopsies from 17 women with benign breast disease and from 11 women with invasive breast carcinoma were investigated using electrophoresis in SDS-containing gradient polyacrylamide gels, followed by Coomassie Blue (CB) staining and the binding of radio-iodinated wheat germ agglutinin (WGA). Patterns were analysed after the CB-step for differences in protein composition, and after the WGA-step for differences in glycoprotein composition. Tissue extracts from patients with benign breast disease have less CB stained bands than similar extracts from the cancer patients. A particular consistent change was the appearance of an extra band at 58 Kdaltons in the cancer extracts. In contrast to the CB results, WGA detected less major bands, in the 40-60 Kd region, in the cancer extracts than at similar locations in benign extracts. Analysis of blood sera using the above techniques suggested that certain serum proteins could account for some of the WGA changes, but not the changes after CB staining. However, residual contamination of the specimens by blood proteins seemed unlikely because of the washing procedure used, unless these components were very strongly associated with the tissue. Differential synthesis of serum proteins by benign and malignant breast tissue may also explain some of our findings. Examination of the histopathology adjacent to the extracted tissue suggested that the degree of reduction in WGA-binding may be related to the extent of local invasiveness. Other animal and human studies suggest that reduced glycosylation of tumour-associated proteins may be linked to increased malignancy. The current findings may reflect a general pattern of change in tumour glycoprotein composition linked to malignant expression.

Peroxidase-labelled lectin binding of human extravillous trophoblast

The binding of four peroxidase-conjugated lectins, concanavalin A (Con-A), wheat germ agglutinin (WGA), peanut agglutinin (PNA) and soybean agglutinin (SBA), in both fixed and frozen tissue sections of human extravillous trophoblast (EVT) was determined. On the basis of its lectin binding properties the EVT cell population was found to be heterogeneous. PNA and SBA did not bind to any of the EVT cells. Con-A and WGA bound to most EVT cells, with the exception of the trophoblast of the chorion laeve. The trophoblast giant cells bound only Con-A and not WGA. The villous cytotrophoblast, from which the EVT cells are said to derive, does not express the sugar groups detected by the above lectin probes. The expression of mannosylated and di-N-acetylchitobiosyl residues by a fetally derived cell invites speculation that such expression enables it both to invade host maternal tissues and to avoid any adverse host immunological response.

Staining for factor VIII related antigen and Ulex europaeus agglutinin I (UEA-I) in 230 tumours. An assessment of their specificity for angiosarcoma and Kaposi's sarcoma

In this study we examined the staining reactivity of commercially available antisera to factor VIII related antigen (F VIII RAg) and Ulex europaeus agglutinin I (UEA-I) on sections from 230 formalin fixed paraffin embedded tumours. These included 196 sarcomas, 20 carcinomas and 14 angiomas. All angiomas showed positive staining for F VIII RAg; all carcinomas showed negative staining; the vasoformative areas of all angiosarcomas stained positively but only four of six angiosarcomas showed positive staining of their solid areas; of seven Kaposi's sarcomas, all showed positive staining of vessels and six showed positive staining of the spindle cell component. In the remaining 181 non-vascular sarcomas there was a false positive result in four tumours (2.2%), three of which had a history of irradiation. Pre-radiotherapy biopsies of these three tumours stained negatively with anti-F VIII RAg. UEA-I was demonstrated in all the angiomas studied, in all angiosarcomas (including the solid components) and in well-formed vessels of all Kaposi's sarcomas, but only in the spindle cell component of 3/6. However, there was an unacceptably high rate of false positive staining amongst the carcinomas and non-vascular sarcomas. In conclusion, F VIII RAg is a specific but not a sensitive marker of angiosarcomas; UEA-I is a sensitive but not a specific marker of angiosarcomas.

The utilization of [3H] sugars by non-malignant and malignant human breast

The utilization of [3H] sugars and leucine by non-malignant and malignant human breast has been assessed using an organ culture technique with subsequent tissue autoradiography. The uptake of sugars by normal and hyperplastic breast was generally constant, with some differences observed in the utilization of galactose by acini of normal and hyperplastic tissues. After 24 h incubation localization was predominantly at the luminal cell periphery. The utilization of sugars by carcinomas was much more variable. Differences were observed between adjacent cells and cell groups of the same tumour. The uptake of individual sugars within a carcinoma was also varied being either similar to, or greater or lesser than normal breast. Variation between carcinomas was also present. No correlation between type and differentiation was noted in this respect, but there was between localization of sugars and differentiation. Better differentiated areas in tumours showed patterns similar to non-malignant breast whilst localization in poorly differentiated cell groups was cytoplasmic. The uptake of leucine was more constant and proved to be a useful indicator of viability. While this approach cannot give information with regard to differences in glycoprotein structure between non-malignant and malignant breast, it has been of value in determining the heterogeneity of tumour cells with regard to the enzymes involved in glycosylation. As such it would be of use in assessing the uniformity of response to agents modifying glycosylation.

Lectin binding and steroid receptors in human breast carcinomas

A series of breast carcinomas of known steroid receptor status have been examined for evidence of binding of the lectins peanut agglutinin, soy bean agglutinin and wheat germ agglutinin. Correlations were found between oestrogen receptor status and reactivity of carcinomas to peanut agglutinin and soy bean agglutinin but these were not absolute. Wheat germ agglutinin binding was unrelated to the presence of oestrogen receptors. No relationship was evident between progestogen receptors and the binding of any lectin. It therefore seems unlikely that lectin histochemistry can replace steroid receptors as markers of hormone dependence in breast carcinomas.

Lectins

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The binding of peroxidase-labelled lectins to human breast epithelium. IV--The reactivity of breast carcinomas to peanut, soy bean and Dolichos biflorus agglutinins

The binding of the lectins from peanut, soy bean and Dolichos biflorus (specific for galactose and/or N-acetyl-D-galactosamine), to human breast carcinomas has been investigated. In contrast to the consistent pattern found in normal breast the reactivity of carcinomas to peanut lectin is varied, the most striking differences being prominent binding without desialation in some tumours and virtual lack of reactivity in others. There tends to be a greater degree of binding of soy bean agglutinin to carcinomas than normal although this is not absolute, and the reverse applies to Dolichos biflorus agglutinin. Comparison of the binding of the three lectins has revealed a complex heterogeneity of the carbohydrate chains within individual tumours and between different carcinomas. A significant relationship between peanut lectin binding, with the use of neuraminidase, and tumour differentiation as been found, and to a lesser extent with soy bean agglutinin when desialation is performed. However, the pattern of reactivity of the carcinomas with these three lectins does not appear to be related to local lymph node metastasis.