Identification of glycoproteins expressing tumour-associated PNA-binding sites in colorectal carcinomas by SDS-GEL electrophoresis and PNA-labelling

Many tumour-specific antigens in gastrointestinal cancers have carbohydrate immuno-determinants. These epitopes can be identified by lectins and monoclonal antibodies. By using fluorescein-isothiocyanate (FITC)-conjugated peanut agglutinin (PNA) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) we have investigated glycoproteins carrying altered carbohydrate epitopes in normal and carcinomatous human colorectal mucosa. In normal mucosa PNA stained goblet cell glycoconjugates in the supranuclear (Golgi) distribution. After neuraminidase pretreatment PNA stained actual mucin goblet itself at all levels of the crypts. Colorectal carcinomas displayed a strong and direct binding of PNA to apical cell membranes of carcinomatous cells and intraluminal secretions. Analysis of the glycoproteins by SDS-PAGE and PNA-labelling revealed four carcinoma-associated glycoproteins (26kD, 32kD, 35kD and 50kD). In addition, four glycoproteins (29kD, 30kD, 33kD and 36kD) common to normal and carcinomatous colorectal mucosa could be identified. All of these glycoproteins differed in their molecular weight from those in red cell controls which bind PNA only after desialylation. The study shows that the expression of PNA-binding sites in colorectal carcinomas signifies a cancer-associated carbohydrate alteration. Four carcinoma-associated glycoprotein antigens could be detected by this lectin. The antigens we have identified might be useful in the isolation and purification of more selective reagents for the serologic detection of colorectal cancer.     

Lectin histochemistry of metastatic adenocarcinomas of the lung

BACKGROUND: Several clinical studies indicate that primary tumour cells with high metastatic potential often show aberrant glycosylation as detected by lectin histochemistry. However, it is unclear whether aberrant glycosylation is still present in metastatic deposits. The aim of the present investigation was thus to analyse a possible association between the presence of lectin binding sites of pulmonary adenocarcinoma cells and their lymph node and haematogenous metastatic cells. METHODS: For this purpose, the expression of HPA, PHA-L and UEA-I was assessed in primary tumours, lymph node metastases and haematogenous metastases of 96 patients with metastatic adenocarcinomas of the lung that underwent surgery between 1999 and 2002. Besides, lectin-binding data and other known prognostic factors were correlated with survival. RESULTS: We found a significant positive correlation between the binding of the lectins HPA (p=0.002), PHA-L (p<0.00001) and UEA-I (p<0.00001) to the cells of the primary tumour and to their lymph node metastases. There was a positive correlation between the binding of HPA to the cells of the primary tumour and the haematogenous metastases as well. Patients with tumours which did not show HPA binding sites had a median overall survival of 27.9 months (95%-CI 7.7-infinity months). Patients with a HPA binding tumour had a median overall survival of 20.9 months (95%-CI 18.5-28.7 months). CONCLUSION: This is the first investigation to demonstrate a positive correlation between the binding of the lectins HPA, PHA-L and UEA-I to the cells of the primary tumour and to their lymph node metastases. Expression of HPA binding sites is also preserved in the haematogenous metastases. In summary, our results support the hypothesis that altered glycosylation of the membrane-bound glycoproteins of the tumour cells is associated with, but not sufficient for promotion of lymphogenic and haematogenous metastasis.     

Regional differences in normal and cancer-associated glycoconjugates of the human colon

Because inherent regional differences in colonic epithelium may determine the biologic behavior of tumors originating from different sites, and inasmuch as colonic epithelial cells secrete mucins that may reflect the state of cell differentiation, colonic goblet cell mucin was analyzed with the use of fluorescein isothiocyanate-conjugated lectins and fluorescence microscopy in normal fetal and adult mucosa and in cancers of the proximal and distal colon. In the adult proximal colon only the goblet cell mucin in the upper portion of the crypts was specifically labeled by the lectin Dolichos biflorus agglutinin (DBA), whereas this gradient was progressively lost distally; mucin in the upper and lower crypts of the sigmoid colon and rectum bound the label uniformly. In fetuses less than 22 weeks of age, DBA bound only to mucin in the crypts of the distal colon. Seven of 12 (58%) cancers originating from the proximal colon bound DBA, whereas only 2 of 23 (9%) from the distal colon bound this lectin (P less than .005). Logistic regression analysis suggested that this difference may reflect the occurrence of larger tumors in the proximal colon. Regional differences in the binding of Ulex europaeus agglutinin (UEA-I) to nonneoplastic mucosa was similar to that found by others; predominant binding occurred in the proximal colon in the adult. No difference was noted for UEA-I binding to tumors of the proximal (8 of 12; 66.6%) versus distal (11 of 23; 48%) colon (P = .48). These findings may reflect regional differences in normal and tumor-related carbohydrate structures in mucin of the human colon.     

Lectin histochemistry of the thyroid gland

The authors carried out a histochemical study with lectins (Ulex europaeus agglutinin-I [UEA-I], Triticum vulgaris [WGA], Glycine max [SBA], Dolichos biflorus [DBA], and Arachis hypogaea [PNA]) in different thyroid gland conditions (17 benign nodular goiters, three diffuse hyperplasias, five Hashimoto's thyroiditis, 20 follicular adenomas, 14 well-differentiated papillary carcinomas, five well-differentiated follicular carcinomas, and 30 normal thyroids) in order to determine if specific lectin patterns are developed during neoplastic transformation. The results showed that (1) in normal thyroid glands, the lectin, UEA-I, is able to discriminate between follicular cells and C-cells; (2) pathologic follicular epithelium had an increased expression of UEA-I, SBA, and WGA receptors; (3) no lectin or group of lectins allow a distinction between follicular carcinoma and papillary carcinoma; (4) when benign and malignant tumors are compared for UEA-I affinity there is a significantly greater frequency of malignant tumour with UEA-I receptor; and (5) although all investigated lectins have shown receptors in endothelial cells at least in one case, the most constant findings have been obtained with UEA-I and WGA. These findings suggest that lectins are not useful in routine diagnostic pathologic examination; however, in particular cases of follicular carcinoma, UEA-I may be a useful tool for the recognition of small vessels invaded by tumoral cells and the demonstration of fucose residues in malignant tumor cells.     

Expression of Gal beta 1-4GlcNAc sequences by human gastrointestinal neoplasms and their precursors as detected by Erythrina cristagalli and Erythrina corallodendron lectins

Lectins from Erythrina cristagalli (EGA) and Erythrina corallodendron (ECorA) are well-known to detect type 2 chain oligosaccharides (Gal beta 1-4GlcNAc). These carbohydrate moieties are the biosynthetic precursors of various ABH and Lewis blood group antigens and are therefore also related to tumor-associated carbohydrate antigens. For this reason, we investigated the expression of ECA and ECorA binding sites in a series of gastric, colorectal and pancreatic carcinomas as well as corresponding normal tissues. Additionally, a series of hyperplastic and adenomatous colorectal polyps was analyzed. According to our results, both lectins exhibited a strong reactivity with the great majority of gastrointestinal carcinomas. Regarding gastric carcinomas, a stronger reactivity with intestinal-type compared to the diffuse-type species could be observed. Some poorly differentiated tumors were not or only very faintly stained. In the case of colorectal carcinomas, liver metastases which were investigated comparatively, exhibited the same binding pattern as the primary tumors. Colorectal adenomas were stained in about half of the cases without significant relation to the grade of cellular atypia. Positivity observed in normal epithelia (i.e, gastric superficial epithelia, fundus neck cells and deep pyloric mucous glands, pancreatic acini and ductal structures) is in keeping with histogenetic relations between these normal histological structures and corresponding neoplasms. In areas exhibiting intestinal metaplasia, various portions showed cytoplasmic staining of columnar cells and/or of goblet cell vacuoles. On the other hand, columnar and goblet cells in normal colorectal tissue were only weakly stained in a number of specimens. Therefore, it can be concluded that Gal beta 1-4GlcNAc is overexpressed in neoplastic colorectal tissues. Summarized, ECA and ECorA are suitable tools to analyze the expression of Gal beta 1-4GlcNAc, the common precursor substance of various tumor-associated type 2 chain antigens in neoplastic tissues.     

Lectin histochemistry as a predictor of dysplasia grade in colorectal adenomas

Lectins are sugar-binding proteins that bind to specific cellular carbohydrates, commonly affecting cellular physiology. Phaseolus vulgaris leucoagglutinin (PHA), ulex europaeus isoagglutinin-I (UEA-I), wheat germ agglutinin (WGA) and peanut agglutinin (PNA) are among the most well studied lectins in various tissues. The purpose of this study was to detect the above lectins binding sites and so examine alterations in glycoconjugate expression in neoplastic cells of 52 colorectal adenomas with various clinicopathologic characteristics and proliferation rates. Lectin histochemistry was performed in paraffin sections with and without neuraminidase treatment. Proliferative fraction was determined by immunolabelling for Proliferating Cell Nuclear Antigen. PHA was the more frequently positive lectin in the examined specimens; however, it was simultaneously detected in normal colonic mucosa and so was WGA. The frequency of high grade dysplasia was significantly greater in older patients and in samples with UEA-I positivity without neuraminidase pretreatment. UEA-I-reactive adenomas were generally characterized by high cell proliferation rates. A statistical model based on patients age and UEA-I binding without neuraminidase treatment can generally predict grade of dysplasia in 83% of adenomas and particularly high grade dysplasia in up to 93% of adenomas; so, such a model may be potentially useful for the early detection of neoplasia, for instance in exfoliative cells from the large intestine.     

Lectin histochemical study of cholagiocarcinoma 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 intraheptic 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 homogenously 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. 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 chollangiocarcinoma, 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 epithelial. This led us to conclude that there is a dramatic decrease in lectin-binding carbohydrate structures associated with cholangiocarcinoma progression.     

Lectin binding affinities of induced pancreatic lesions in the hamster model

We examined the binding pattern of nine lectins to N-nitrosobis(2-oxopropyl)amine(BOP)-induced pancreatic lesions in Syrian hamsters. These lectinswere Arachis hypogaea(PNA), Dolichos biflorus (DBA), GriffoniasimplicifoliaI(GS-I), Helix aspersa(HAA), Helix pomatia (HPA),Sophora japonica (SJA), Ricinus communisI(RCA-I), Triticum vulgaris(WGA) and Ulex europaeus I (UEA-I). All of the lectins reactedin untreated control hamsters to varying intensities with cytoplasmiccomponents of acinar cells. GS-I, HPA, RCA-I and UEA-I boundto the basolateral surface and PNA, HAA and HPA to the luminalsurface of these cells. All but GS-I, RCA-I and UEA-I stainedthe cytoplasm of islet cells diffusely. In untreated controlhamsters, some ductal cells bound PNA, HAA and RCA-I, whereasthese cells reacted negatively to the remaining six lectins.Ductular cells did not bind any of the nine lectins. Hyperplasticductal cells in untreated hamsters were reactive with all ninelectins; however the intensity of the reactivity, cellular localizationand extent differed for each lectin. In carcinogen-treated hamsters,the binding pattern of the lectins to acinar and islet cellsdid not differ significantly from that in untreated hamsters,whereas cells of induced ductal and ductular lesions bound eachof the lectins in different patterns and intensities. The reactionof UEA-I to induced lesions was most consistent, specific andstrong, thereby indicating the presence of L-fucose in glycoproteinsproduced by altered cells. Although the binding affinity ofthe lectins to induced hyperplastic lesions differed in botha quantitative and qualitative fashion, all dysplastic and malignantlesions were reactive to each lectin. This result indicatesa heterogeneity in the carbohydrate structure of the glycoproteinsproduced by pancreatic cells during carcinogenicity.     

荆豆凝集素(UEA-Ⅰ)受体的定位分布对诊断鼻咽癌前病变的初步观察

用亲合组织化学技术,以UEA—I,ConA,PNA三种凝集素对30例鼻咽上皮重度不典型增生、化生(癌前病变),70例鼻咽癌及30例正常鼻咽粘膜上皮进行观察对比,了解其分布定位及含量的差异。结果发现:荆豆凝集素(UEA—I)在正常鳞状上皮多呈膜性分布;鼻咽癌癌细胞多呈阴性反应;而鼻咽癌前病变的细胞则显示膜性及胞浆性强阳性反应,与正常上皮及癌巢对比鲜明,UEA—I还能显示间质异常增生的血管,说明它是一种协助诊断鼻咽癌前病变很有希望的一种凝集素。而PNA及ConA则对鼻咽癌前病变的诊断价值不大。     

Pyloric gland phenotypic expression of gastric cancers developing in the rat fundic glandular stomach

Mucin histochemistry of experimental gastric cancers induced in rats by N-methyl-N'-nitro-N-nitrosoguanidine or 4-nitroquinoline 1-oxide was analysed by labelled lectin staining for concanavalin A (Con A) after prior periodate oxidation (paradoxical Con A staining) or Arachis hypogarea agglutinin (peanut lectin, PNA) with or without prior periodate oxidation. In the digestive tracts of control-group rats the mucins were classified into class II or III by paradoxical Con A staining. Class II mucins were found in surface mucous cells, goblet cells and the surface coat of intestinal absorptive cells, while class III mucins were present in mucous neck cells, pyloric gland cells and Brunner's gland cells. Although class III mucins showed PNA reactivity, those in pyloric gland cells selectively lost positive staining after 1-4 h oxidation with periodate. Thus phenotypic expression of class III mucin-positive cells in the gastric mucosa could be further classified into mucous-neck-cell type and pyloric-gland-cell type on the basis of this sensitivity to periodate oxidation. Metaplastic cells in fundic mucosa and almost all class III mucin-positive cells in adenomatous hyperplasias, well-differentiated adenocarcinomas and signet-ring cell carcinomas, which developed in both fundic and pyloric mucosae, showed pyloric gland phenotypic expression.     

Lectin binding patterns in diffuse large cell lymphoma

The staining reaction of a panel of lectins in paraffin embedded lymph node specimens of diffuse large cell lymphoma was studied in relation to survival. In 47 of 49 patients, varying degrees of lectin binding were observed with Ricinus communis agglutinin (RCA), crude extract of Arachis hypogaea (c-PNA), Concanavalin ensiformis A (Con A), Triticum vulgaris A (WGA) and Phaseolus vulgaris A (PHA). Binding was either absent or only minimal with Pisum sativum A (PSA) and Lens culinaris A (LCA). Two categories of binding were observed: cell surface and cytoplasmic. Cell surface binding was seen in tumor cells, while cytoplasmic binding was observed in macrophage-histiocytes. Varying numbers of tumor cells were stained with RCA, WGA, c-PNA or PHA; but with Con A virtually no tumor cells were stained. Stromal macrophage-histiocytes were stained with RCA, WGA, or Con A in all but one case, frequently with all three lectins; c-PNA binding macrophage-histiocytes were absent in one third of the cases. With PHA the staining of stromal macrophage-histiocytes was extremely rare. Tumor cells that stained with RCA but not with c-PNA were observed in 9 of 15 patients who survived more than 2 years after diagnosis. In all 15 long-term survivors, stromal macrophage-histiocytes were positive for c-PNA. Tumor cells that reacted with c-PNA but not with RCA were seen in five patients who survived less than two years. All 16 patients whose tumors lacked c-PNA binding stromal macrophage-histiocytes in the presence of RCA binding macrophage-histiocytes were short-term survivors. These observations suggest the heterogeneity of stromal macrophage-histiocytes as well as that of tumor cells. Furthermore, the variation of lectin binding might be useful in assessing prognosis.     

A new mucin-associated oncofetal antigen, a marker of early carcinogenesis in rat colon

We report the characterization of an IgG2a monoclonal antibody, (MAb) 660, prepared against rat gastric high molecular weight glycoproteins. By immunoperoxidase staining, MAb 660 reacted only with the mucous cells of surface gastric epithelium and with a few duodenal goblet cells close to the pylorus in normal adult rats. In fetuses, it reacted with intestinal and colonic goblet cells. The adult colon was always negative. The MAb 660 stained 100% (30 of 30) of chemically induced colonic carcinomas and 100% (7 of 7) of duodenal carcinomas. Several weeks before the appearance of tumors, histologically normal glands, then hyperplasia and dysplasia were precociously stained with MAb 660. The tissue distribution was different from that of blood group related antigens and M1 fucomucins. The recognized antigen was not sensitive to neuraminidase treatment. After electrophoresis in polyacrylamide gel, staining with periodic acid-Schiff reagent and Western blotting showed that the MAb 660 recognized an epitope associated with high molecular weight glycoproteins. This epitope was unaffected by beta-mercaptoethanol reduction-periodate treatment and neuraminidase and trypsin digestion. However, trypsin digestion performed after beta-mercaptoethanol reduction destroyed the 660 epitope. These data suggest that the antibody could recognize the peptide moiety of the mucin rather than its carbohydrate moiety. Thus, the new antigen identified by MAb 660 is a mucin-type glycoprotein with an oncofetal behavior in the rat colon and is precociously expressed by precancerous colonic mucosa.     

Antigens of gastric and intestinal mucous cells in human colonic tumours.

Using immunofluorescence methods, 3 antisera respectively stain 3 groups of mucous cells of the human gastrointestinal tract, showing specific antigens for each group of cells. The antigens of the first group, the M1 antigens, were principally associated with columnar cells of the gastric epithelium, the M2 antigens with mucous cells of gastric and Brünner''s glands, and the M3 antigen with the goblet cells of the intestinal mucosa. The gastric M antigens normally detectable in stomach and duodenum (but not in colon) were expressed in certain colonic tumours (benign or malignant) and in adjacent mucosa. They are always present with the intestinal M3 antigen. In 100 colonic adenocarcinomas, the intestinal M3 antigen was found in 53 cases, gastric M1 antigens in 29 cases, and gastric M2 antigens in 10 cases, always with the two other M antigens. A good correlation could be established between the association of M antigens and the histological type of tumour.     

Fetal and ectopic mucous markers expressed by distal and proximal rat colonic carcinomas

Using immunohistochemistry, seven markers associated with mucous glycoproteins were studied in rat colonic mucosa during fetal and adult life and in carcinomas. These included: blood group A antigen, terminal fucose, sulfated and sialylated groups, M3 intestinal, M3C colonic and M1 gastric antigens. It was found that colonic carcinomas expressed normal adult markers, fetal markers and an ectopic marker. The differentiation of goblet cells was not the same in distal and proximal colon. Finally, this differentiation shared numerous analogies with that of human colonic goblet cells.     

Isolation of a sulfated glycopeptidic antigen from human gastric tumors: its localization in normal and cancerous gastrointestinal tissues.

A sulfated glycopeptidic antigen (SGA) was purified from papain-digested cancerous human gastric mucosa. The amino acid composition of this antigen was characterized by a high percentage of threonine and proline. Serine was present in small quantities and aromatic amino acids were absent. The amount of sulfate present was evaluated at 7.5%. Fucose, galactose, N-acetyl glucosamine, N-acetyl galactosamine and sialic acid were found to be present in the molar ratio 1:4.6:3.0:6.2:5.0. With immunofluorescence techniques, a rabbit antiserum against the sulfated glycopeptide stained adult gastric mucosa when this tissue had intestinal metaplasia and stained the goblet cells of the intestinal tract (small and large intestines). About 50% of colonic carcinomas and some gastric carcinomas contained SGA. This sulfated antigen was present in well-differentiated tumors and there was a good correlation between tumoral acid mucous secretory activity and the SGA positivity.     

Carbohydrate profiling of fungal cell wall surface glycoconjugates of Trichophyton tonsurans and other keratinophilic filamentous fungi using lectins

Various researchers have concluded that lectins are useful reagents for the study of fungal cell wall surface glycoconjugates. In this study, we evaluated the expression of N-acetyl-D-glucosamine, L-fucose, D-galactose and glucose/mannose on the cell wall surface of Trichophyton tonsurans and other keratinophilic filamentous fungi, using a simple lectin-binding protocol. The fungal cultures used were isolated from soils obtained from public parks by the hair-bait technique. The lectin assays used concanavalin A (Con A), wheat germ agglutinin (WGA), Ulex europeus agglutinin I (UEA-I) and peanut agglutinin (PNA), all conjugated with horseradish peroxidase. Adhesive tape was placed sticky-side down over the fungal colony, gently pressed and then removed. The fungal-tape samples were incubated with the lectin for 1 h at 4 °C. Lectin binding was visualised using 3,3-diaminobendizine (DAB) and hydrogen peroxidase. There was a high expression of N-acetyl-D-glucosamine on the cell wall surface of all fungi species tested, whereas the expression of L-fucose, D-galactose and glucose/mannose demonstrated inter-specific variations. The lectin-binding assay presented in this article eliminates many of the laborious steps involved in other protocols. The amount and quality of the mycelium and spores immobilised by the adhesive tapes were suitable for obtaining the carbohydrate profile in glycoconjugates of the cell wall surface of filamentous fungi.     

Lectin histochemistry of adenomatous polyps. Not a predictor of metachronous lesions

The binding characteristics of fluorescein isothiocyanate conjugated lectins to normal colonic mucosa, and 43 adenomatous polyps were studied by fluorescence microscopy. The lectin, Dolichos biflorus agglutinin (DBA) stained intensely to upper crypt cells of the sigmoid colon and rectum but to a lesser degree to proximal colonic crypts or lower crypt cells distally. Peanut agglutinin (PNA) and Ulex europaeus agglutinin (UEA) did not bind to the theca of proximal or distal colonic crypts. The lectin Griffonia simplicafolia agglutinin (GSA1) bound intensely to upper and lower crypt cells of both regions. PNA binding was noted in 56% of adenomatous polyps, occurred more often in polyps of the distal colorectum, and increased with polyp size and villous histology. UEA bound to 26% of adenomatous polyps, 42% of proximal polyps, and 17% of distal polyps. DBA staining was noted in 72% of polyps without regional preference. GSA1 stained all polyp specimens. To determine if the lectin binding characteristics of an index (initial) polyp might serve as a predictor of metachronous lesions, 20 patients (29 polyps) without a history of polyps or cancer and who had at least one surveillance colonoscopy 1 to 3 years after the initial polypectomy were studied. The presence or absence of PNA, UEA, or DBA binding in an index polyp did not predict the occurrence of metachronous lesions. Five of the six patients with more than one index polyp had metachronous polyps at follow-up surveillance colonoscopy.     

Carcinoma-specific Ulex europaeus agglutinin-I binding glycoproteins of human colorectal carcinoma and its relation to carcinoembryonic antigen

Glycoproteins binding to Ulex europaeus agglutinin-I (UEA-I) lectin, which recognizes the terminal alpha-L-fucose residue, were analyzed in 18 cases of human colorectal carcinoma by sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by the Western blotting method. In the distal large bowel (descending and sigmoid colon and rectum), high-molecular-weight glycoproteins binding to UEA-I existed in carcinoma tissue but not in normal mucosa. In the proximal large bowel (ascending and transverse colon), high-molecular-weight glycoproteins binding to UEA-I were found both in normal mucosa and in carcinoma tissue, whereas those from the carcinoma tissue had an apparently lower molecular weight as compared to the weight of those from the normal mucosa. Thus there is a biochemical difference in UEA-I binding glycoproteins between the normal mucosa and the carcinoma tissue, although in our previous histochemical study no difference was observed in UEA-I binding glycoproteins of the proximal large bowel between the carcinoma tissue and the normal mucosa. Furthermore, carcinoembryonic antigen from the carcinoma tissue was found to have the same electrophoretical mobility as the UEA-I binding glycoproteins.     

Relationship between the Nature of Mucus and Crypt Multiplicity in Aberrant Crypt Foci in the Rat Colon

Aberrant crypt foci (ACF)induced in the distal colon of F344 male rats, 4, 8, 12 and 35 weeks after the first administration of 1, 2-dimethylhydrazine-2HCl (DMH) were examined to determine whether a correlation exists between the nature of goblet cell mucin and the number of crypts (crypt multiplicity) comprising the ACF. According to the ACF score calculated from the results of the qualitative observation of sulfomucins (SuMs) and sialomucins (SiMs), the ACF in the 4th week showed a weak correlation between the nature of the mucus and crypt multiplicity, and the ACF of each class showed similar mucous profiles. From the 8th week, a significant difference ( P <0.01) was recognized between the ACF consisting of 3 crypts or less and those consisting of 4 crypts or more. The proportion of crypts with SiM predominance showed a decrease in the 8th.week in the ACF consisting of 1 crypt and in the 12th week in the ACF consisting of 2 or 3 crypts, implying a recovery tendency. The ACF consisting of more than 4 crypts showed little change over time, retaining the tendency of SiM predominance. Ulex europaeus agglutinin-I (UEA-I) lectin-positive crypts appeared in the ACF. This finding was significantly more prominent ( P < 0.001) in the ACF with SiM predominance than in the ACF with SuM predominance at each experimental period, and in the 12th week after the first administration of DMH, the incidence of ACF with UEA-I-reactive mucin was decreased in the ACF groups consisting of 3 crypts or less, compared with the ACF groups consisting of 4 or more crypts.These results suggest that the biological quality of mucus in ACF consisting of 4 or more crypts is different from that in ACF consisting of 3 crypts or less. This difference should be considered when ACF are used as an intermediate biomarker of colon cancer.     

Lectin bindings in non-neoplastic esophageal epithelium and esophageal carcinomas

Lectin binding was examined histochemically in 22 cases of primary esophageal carcinomas (10 well differentiated, 8 moderately differentiated and 3 poorly differentiated squamous cell carcinomas, and 1 undifferentiated carcinoma) and was compared with the adjacent non-neoplastic epithelium by means of a panel of 10 different lectins (RCA-I, WGA, Con A, LCA, SEA, UEA-I, HPA, PNA, DBA and GS-I) on formalin-fixed paraffin-embedded sections. In the non-neoplastic epithelium, RCA-I and WGA showed basal/parabasal binding, Con A, LCA, SEA, UEA-I, HPA and PNA revealed prickle cell binding, while DBA and GS-I only stained the surface cells of the squamous cell layer. In squamous cell carcinomas, no clear difference was evident regarding the grade of differentiation. However, basal/parabasal specific lectins were expressed in all the cases, the prickle cell-specific lectins were expressed less frequently, whereas lectins expressed at the surface cells of the squamous cell layer were only infrequently expressed. Therefore, basal/parabasal cell specific lectins were widely preserved in squamous cell carcinomas. One case of undifferentiated cancer tested was devoid of all the lectins.