Immunohistochemical study of the expression of MUC6 mucin and co-expression of other secreted mucins (MUC5AC and MUC2) in human gastric carcinomas.

To investigate the expression of MUC6 mucin in gastric carcinomas, we generated a novel monoclonal antibody (MAb CLH5) using an MUC6 synthetic peptide. MAb CLH5 reacted exclusively with the MUC6 peptide and with native and deglycosylated mucin extracts from gastric tissues. MAb CLH5 immunoreactivity was observed in normal gastric mucosa restricted to pyloric glands of the antrum and mucopeptic cells of the neck zone of the body region. In a series of 104 gastric carcinomas, 31 (29.8%) were immunoreactive for MUC6. The expression of MUC6 was not associated with histomorphological type or with clinicopathological features of the carcinomas. Analysis of the co-expression of MUC6 with other secreted mucins (MUC5AC and MUC2) in 20 gastric carcinomas revealed that different mucin core proteins are co-expressed in 55% of the cases. MUC6 was co-expressed and co-localized with MUC5AC in 45% and with MUC2 in 5% of the cases. Expression of MUC2 alone was observed in 25% of the cases. All carcinomas expressing MUC2 mucin in more than 50% of the cells were of the mucinous type according to the WHO classification. The co-expression of mucins was independent of the histomorphological type and stage of the tumors. In conclusion, we observed, using a novel well-characterized MAb, that MUC6 is a good marker of mucopeptic cell differentiation and is expressed in 30% of gastric carcinomas, independent of the clinicopathological features of the cases. Furthermore, we found that co-expression and co-localization of mucins in gastric carcinomas is independent of histomorphology and staging. Finally, we observed that intestinal mucin MUC2 is expressed as the most prominent mucin of the mucins tested in mucinous-type gastric carcinomas.     

p53突变蛋白在胃癌组织中的表达及免疫电镜观察

作者应用抗ｐ５３单克隆抗体Ｐａｂ１８０１（Ａｂ２美国癌基因公司产品）对３８例手术切除的胃癌组织及癌旁胃粘膜的冰冻切片标本进行ｐ５３突变蛋白表达的检测,并进一步用胶体全免疫电镜技术对ｐ５３突变蛋白的分布特征进行观察。结果：３８例胃癌组织中,２４例有ｐ５３突变蛋白高表达,阳性率６３．２％。在对应的癌旁胃粘膜中１０例为ｐ５３的弱表达,正常组织无表达。伴有淋巴结转移的２３例胃癌标本中,１８例ｐ５３高表达（７８．３％）。免疫电镜结果表现,ｐ５３蛋白主要分布于核内染色质中,胞浆中有散在的阳性区,但以核膜周边为主,紧靠核膜。本研究结果提承胃癌的发生及其肿瘤的生物学行为与抑癌基因ｐ５３的突变密切相关,ｐ５３突变蛋白可能是通过对ＤＮＡ复制的影响而参与肿瘤的形成。     

Ultrastructural observations on the microvasculature in advanced gastric carcinomas

The ultrastructural features associated with vascular permeability in 9 cases of advanced gastric carcinomas were studied, and compared with that of control non-neoplastic mucosa. Tumour microvasculature showed features in common with those of control mucosa, including complete basal lamina, well-developed interendothelial junctions, fenestrations and caveolae. Some tumour blood vessels showed endothelial cell swelling accompained by luminal narrowing and perivascular fibrosis. In 2 out of 9 cases, there were endothelial attenuation with numerous fenestrations and vesiculo-vacuolar organelles. The vesiculo-vacuolar organelle is a recently described cytoplasmic structure found in the endothelial cells lining tumour microvessels and normal venules and which provides an important pathway for extravasation of circulating macromolecules. Our ultrastructural data suggest that advanced gastric carcinomas share with experimental tumour models in vivo only some morphologic features associated with hyperpermeability including fenestration, endothelial attenuation and vesiculo-vacuolar organelles. The implications of perivascular fibrosis on the delivery of immune cells to gastric carcinomas are discussed.     

Distribution of the carcinoembryonic antigen CEA in gastric lesions. Immunohistochemical testing of three novel monoclonal antibodies

Three mouse monoclonal antibodies MAB (CEA 12-140-1, -2 and -4) raised against different CEA epitopes were tested in 32 gastric adenocarcinomas (18 intestinal type and 14 diffuse type) and 34 gastric lesions with severe and moderate dysplasia. The MAB stained 13, 11 and 13 out of the 14 diffuse carcinomas and 11, 13 and 13 out of the 18 intestinal carcinomas. The dysplastic lesions were positive in 9, 9 and 6 out of 34 cases. Less than half of the cases with metaplastic epithelium adjacent to the carcinomas were also positive for MAB. All MAB showed the same pattern of reactivity without cross-reactivity. Their cumulative staining rate corresponded closely to that of polyclonal CEA antiserum, but the MAB stained more cells. The reactivity was confined to intracytoplasmic vacuoles in diffuse carcinomas and appeared diffusely in the cytoplasm or limited to the cell membrane in intestinal type of carcinomas. Our findings do not indicate CEA to be a reliable marker for malignant transformation in gastric mucosa.     

Secretion and activation of the rennin by the rabbit's stomach

The mucosa of the rabbit's stomach has been studied histochemically, electron microscopically and fluorescence immunologically. The main purpose was to find out whether or not this mucosa secrets the enzyme rennin. During the first two weeks after birth, the gastric glands are composed of only undifferentiated cells. The differentiation of these glands into cardiac, fundic and pyloric glands coincides with the final stage of this period. In the course of the period mentioned the P.A.S.-positive material and the fluorescence induced by rennin exhibit a similar location in the apical cytoplasm of the epithelial cells lining the mucosal surface, the gastric pits and the necks of gastric glands. In the light of these findings, the elaboration and activation of the enzyme rennin is being discussed.     

LMP-1在胃癌和相应癌旁组织中的表达

目的探讨Epstein-Barr virus(EBV)感染与胃癌发生发展的关系。方法应用免疫组化SP法检测EB病毒潜伏感染膜蛋白-1(LMP-1)在97例胃癌组织及89例相应癌旁组织中表达。结果97例胃癌组织中30例LMP-1蛋白表达阳性,阳性率为30.9%,EBV阳性率与患者性别、浸润深度、淋巴结转移、组织学分型和临床分期之间无明显关系(P>0.05);89例相应癌旁组织中33例检测到EBV LMP-1的表达,胃癌组织及相应癌旁组织EBV阳性表达之间有显著相关性(P=0.000)。结论EBV感染与胃癌的发生有一定的相关性。     

Immunocytochemical localization of rabbit gastric lipase and pepsinogen

Lipase and pepsin activities were determined in rabbit gastric biopsy specimens. Lipase activity was found to be restricted to a small part of the fundic mucosa, near the cardia, whereas pepsin activity spread over about two thirds of the total fundic area, overlapping that of lipase. The cells producing these two enzymes were labeled by immunofluorescence using polyclonal antibodies against rabbit gastric lipase (RGL) or antibodies against rabbit pepsinogen. The immunocytochemical localization showed unequivocally that RGL and pepsinogen, which were both present in the cardial area, were in fact located in different gastric cells. The cells producing pepsinogen were in the lower base of the gastric fundic glands, whereas the cells producing RGL were in the upper base of the same glands. The cells producing pepsinogen and RGL showed no significant morphological differences. In the part of the fundic area, where only pepsin activity was detected, cells producing pepsinogen covered both the lower and the upper base of the gastric glands. No chief cells were observed in the antral mucosa. RGL and pepsinogen could represent useful gastric enzyme markers for cellular differentiation studies.     

Lectin binding patterns in normal, metaplastic, and neoplastic gastric mucosa.

We investigated lectin binding patterns on tissue specimens of normal and metaplastic gastric surface mucosae, gastric adenomas, and intestinal and diffuse-type gastric carcinomas. Compared with normal gastric mucosa, metaplastic mucosa exhibited an increase of ConA binding and decreases of WGA, PNA, UEA-1, and DBA binding in the cytoplasm, and decreases of ConA, PNA, and UEA-1 binding at the luminal surface. Intestinal carcinomas were similar to metaplastic gastric surface mucosa in ConA, WGA, and UEA-1 binding in the cytoplasm, while diffuse-type carcinomas were similar to normal gastric mucosa in WGA and UEA-1 binding in the cytoplasm. Adenomas were similar to intestinal carcinomas in ConA and UEA-1 binding in the cytoplasm, but were different from intestinal carcinomas in Con A and UEA-1 binding at the luminal surface. For UEA-1, normal and metaplastic gastric surface mucosae did not show a significant difference between the blood type A, AB, B group and the O group. Intestinal and diffuse carcinomas and adenomas also did not show such a difference between the blood groups. For DBA, normal gastric surface mucosa showed a significant difference between the blood type B, O group and the A, AB group. Normal gastric mucosa of the blood type A, AB group was frequently positive for DBA binding in the cytoplasm and at the luminal surface. Metaplastic mucosa did not show a significant difference between the blood groups. Intestinal and diffuse-type carcinomas and adenomas also did not show a difference between the blood groups. DBA binding in the cytoplasm of intestinal carcinomas and adenomas was more frequently positive than that of normal and metaplastic mucosae, except for normal gastric mucosa of the blood type A, AB group. Compared with diffuse-type carcinomas, intestinal carcinomas were accompanied by a significant increase of ConA binding and decreases of WGA and PNA binding in the cytoplasm.     

Light and Electron Microscopy of the European Beaver (Castor fiber) Stomach Reveal Unique Morphological Features with Possible General Biological Significance

Anatomical, histological, and ultrastructural studies of the European beaver stomach revealed several unique morphological features. The prominent attribute of its gross morphology was the cardiogastric gland (CGG), located near the oesophageal entrance. Light microscopy showed that the CGG was formed by invaginations of the mucosa into the submucosa, which contained densely packed proper gastric glands comprised primarily of parietal and chief cells. Mucous neck cells represented <0.1% of cells in the CGG gastric glands and 22–32% of cells in the proper gastric glands of the mucosa lining the stomach lumen. These data suggest that chief cells in the CGG develop from undifferentiated cells that migrate through the gastric gland neck rather than from mucous neck cells. Classical chief cell formation (i.e., arising from mucous neck cells) occurred in the mucosa lining the stomach lumen, however. The muscularis around the CGG consisted primarily of skeletal muscle tissue. The cardiac region was rudimentary while the fundus/corpus and pyloric regions were equally developed. Another unusual feature of the beaver stomach was the presence of specific mucus with a thickness up to 950 µm (in frozen, unfixed sections) that coated the mucosa. Our observations suggest that the formation of this mucus is complex and includes the secretory granule accumulation in the cytoplasm of pit cells, the granule aggregation inside cells, and the incorporation of degenerating cells into the mucus.     

Different subclass distribution of IgA-producing cells in human lymphoid organs and various secretory tissues

A highly reproducible paired immunofluorescence staining method was used to map the relative distribution of IgA1- and IgA2-producing cells in peripheral lymphoid organs and various secretory tissues. Spleen, peripheral lymph nodes, and tonsils all contained a marked predominance (91 to 95%) of IgA1 immunocytes. However, striking variations were demonstrated among the secretory tissues with regard to the median proportion of IgA1-producing cells: nasal mucosa, 96%; lacrimal glands, 81%; major salivary glands, 66%; mammary glands, 63%; gastric and proximal small intestinal mucosa, 84 to 77%; ileum, 55%; and large bowel, 41%. Thus, IgA2 production is relatively enhanced mainly in the distal gut and in mammary and salivary glands, in that order.     

Endocrine profile in gastric carcinomas. An immunohistochemical study.

22 gastric carcinomas (13 intestinal type and nine diffuse type) were immunostained for neuron specific enolase, chromogranin, Leu-7 and a panel of fifteen different peptide hormones. Five out of the 13 tumours of intestinal type and four out of the nine diffuse carcinomas expressed immunoreactivity for one or more of the pan endocrine markers. Seven out of the 13 tumours of intestinal type and five out of the nine diffuse carcinomas also expressed immunoreactivity for gastrin (3), ACTH (3), serotonin (7) and calcitonin (7). Immunoreactivity for somatostatin (1) and substance P (1) were also seen in two tumours of intestinal type. Seven out of 18 cases with benign mucosa adjacent to the tumours expressed a focal immunoreactivity for chromogranin (6), serotonin (6), gastrin (5) and calcitonin (1). All hormone-producing tumours also expressed immunoreactivity for carcino-embryonic antigen. Our results confirm that a high proportion of gastric carcinomas are hormone producing.     

Immunohistochemical detection of metallothionein in carcinomatous and normal human gastric mucosa

Utilising a specific monoclonal mouse antibody (E9), metallothionein (MT) expression has been immunohistochemically investigated in 112 formalin-fixed paraffin-embedded surgical gastric samples, 38 of which were early carcinomas (EGC) and 74 advanced ones (AGC); clinico-pathological details and follow-up data (ranging from 3 to 197 months, mean 60.5 months) were available. Eighty-nine portions of gastric mucosa adjacent to examined carcinomas (transitional mucosa) were also analysed; in addition, 22 biopsies of normal gastric mucosa were studied as tissue control. The MT immunoreactivity was evaluated by staining and intensity-distribution scores. A various MT positivity was appreciable in the cytoplasm and nucleus of antrum or body gastric epithelial cells in 100% of normal control biopsies. 75/112 (67%) gastric carcinomas showed MT immunoreactivity with a significant lower expression in AGC. No relationships were encountered between MT immunostaining and clinico-pathological data; in addition, no difference in the Kaplan-Meier survival curves of patients with various MT expression was achieved. When the transitional mucosa was examined, 84/89 (94%) samples were stained although the immunoreaction was not always concordant with that encountered in adjacent carcinomatous elements. The significant statistical decrease of MT scores observed by us moving from normal to neoplastic gastric mucosa allows us to exclude the hypothesis of an overexpression of MT in gastric carcinomas.     

Expression of basic fibroblast growth factor in human gastric carcinomas.

The expression of mRNA for the basic fibroblast growth factor (FGF) gene was examined in seven human gastric carcinoma cell lines and in tissue from 29 gastric carcinomas together with the adjacent normal mucosa. Among the seven gastric carcinoma cell lines, the MKN45 cell line expressed mRNA for the basic FGF gene. Basic FGF protein production was confirmed by flow cytometric analysis and immunohistochemistry. Among the surgical specimens, 16 (55%) of 29 gastric carcinomas showed higher levels of basic FGF mRNA than the normal mucosa. Interestingly, in scirrhous gastric carcinomas characterized by their fibrous stroma and rapid growth, 9 (69%) of 13, samples examined revealed higher levels of basic FGF mRNA than normal mucosa, whereas only 3 (33%) of the 9 well differentiated adenocarcinomas studied produced similar results. Immunohistochemically, basic FGF protein was localized in tumor cells. These results suggest that basic FGF produced by tumor cells may play an important role in producing fibrosis and angiogenesis in gastric carcinomas.     

Genetic and epigenetic alterations of tumor suppressor and tumor-related genes in gastric cancer

Both genetic and epigenetic alterations of tumor suppressor and tumor-related genes involved in the pathogenesis of gastric cancer are reviewed here, and molecular pathways of gastric carcinogenesis are proposed. Gastric carcinomas are believed to evolve from native gastric mucosa or intestinal metaplastic mucosa that undergoes genetic and epigenetic alterations involving either the suppressor pathway (defects in tumor suppressor genes) or mutator pathway (defects in DNA mismatch repair genes). Methylation of E-cadherin in native gastric mucosa results in undifferentiated carcinomas (suppressor pathway), while methylation of hMLHI results in differentiated foveolar-type carcinomas (mutator pathway). The majority of differentiated gastric carcinomas however, arise from intestinal metaplastic mucosa and exhibit structural alterations of tumor suppressor genes, especially p53. They appear to be related to chronic injury, perhaps due to Helicobacter pylori infection. Approximately 20% of differentiated carcinomas (ordinary-type) have evidence of mutator pathway tumorigenesis. Mutations of E-cadherin are mainly involved in the progression of differentiated carcinomas to undifferentiated tumors. The molecular pathways of gastric carcinogenesis depend on the histological background, and gastric carcinomas show distinct biological behaviors as a result of discernible cellular genetic and epigenetic alterations.     

Expression of basic fibroblast growth factor in human gastric carcinomas

The expression of mRNA for the basic fibroblast growth factor (FGF) gene was examined in seven human gastric carcinoma cell lines and in tissue from 29 gastric carcinomas together with the adjacent normal mucosa. Among the seven gastric carcinoma cell lines, the MKN45 cell line expressed mRNA for the basic FGF gene. Basic FGF protein production was confirmed by flow cytometric analysis and immunohistochemistry. Among the surgical specimens, 16 (55%) of 29 gastric carcinomas showed higher levels of basic FGF mRNA than the normal mucosa. Interestingly, in scirr-hous gastric carcinomas characterized by their fibrous stroma and rapid growth, 9 (69%) of 13, samples examined revealed higher levels of basic FGF mRNA than normal mucosa, whereas only 3 (33%) of the 9 well differentiated adenocarcinomas studied produced similar results. Immunohistochemically, basic FGF protein was localized in tumor cells. These results suggest that basic FGF produced by tumor cells may play an important role in producing fibrosis and angiogenesis in gastric carcinomas.     

胃癌神经内分泌细胞免疫细胞化学的研究

９６例胃癌应用铬粒素抗体免疫细胞化学法发现３８例（３９．６％）肿瘤含有神经内分泌细胞（ＮＥ细胞）;呈激素阳性者：血清素５例,生长抑素５例,胰多肽５例,胰高血糖素５例,胃泌素３例,ＡＣＴＨ６例。结果显示：ＮＥ细胞发现率及细胞数量在低分化癌中明显高于高、中分化癌;异位激素──ＡＣＴＨ阳性细胞数量在低分化癌也明显多于高、中分化癌;本位激素阳性细胞在ＮＥ细胞中的比例在非肿瘤性粘膜中明显高于癌组织,在原发肿瘤明显高于转移灶,在正常粘膜又明显高于癌旁粘膜。根据上述结果,对ＮＥ细胞的发现率、方法学及其激素产物进行了讨论。     

Mucosal nerves and smooth muscle relationships with gastric glands of the opossum: an ultrastructural and three-dimensional reconstruction study

The precise anatomical relation by which autonomic nerve endings contact gastric epithelial cells to enhance the rate of gastric secretions is not fully understood. The aim of the present study was to clarify this issue by using the technique of serial section reconstruction of areas of the gastric mucosa. The work also explored the possibility of a functional role for a system of smooth muscle strands in the gastric mucosa that emanate from the muscularis mucosa, run in the lamina propria, and are associated in a unique manner with the gastric glands. Electron microscopic serial sections of the gastric mucosa were performed to visualize the entire limiting membrane of gastric epithelial cells to determine any nerve associations (especially varicose endings) with these cells. Evaluation of serial sections of five separate parietal cells showed that their basal membrane did not come in close contact (nearest distance 500 nm) with any nerve axon or varicosity. Moreover, the axons passing in the area of these cells ultimately showed varicose endings associated with smooth muscle cells in the adjacent connective tissue (often separated by only 20 nm), with mast cells or with vascular elements. Additionally, the lateral membrane of these five parietal cells did not contact any endocrine cell in the epithelium, although other parietal cells in the area were adjacent to endocrine cells. Chief cells in the immediate area also did not form any close associations with nerve varicosities. Random analysis of 5,000 additional epithelial cells in these sections showed no close associations to nerve elements with significant accumulations of neurosecretory vesicles (varicosities). Because of the observed existence of innervation to the smooth muscle strands in the area of the gastric glands, serial 1-micron epoxy sections of the gastric mucosa were prepared, and profiles of smooth muscle and gastric glands were entered into a computer-assisted reconstruction system. Three-dimensional reconstruction techniques were employed to reveal the existence of a unique association between the mucosal smooth muscle strands and the gastric glands. The muscle strands arose from the muscularis mucosa at regular intervals and became branched to form an intricate wrap around a series of gastric glands that empty into one gastric pit.(ABSTRACT TRUNCATED AT 400 WORDS)     

Terminal alpha1,4-linked N-acetylglucosamine in Helicobacter pylori-associated intestinal metaplasia of the human stomach and gastric carcinoma cell lines.

Helicobacter pylori (Hp) infection is associated with the development of gastric lesions including gastritis, intestinal metaplasia (IM), and gastric carcinoma. In humans, Hp is found almost exclusively in the foveolar epithelium of the gastric mucosa and rarely colonizes the deeper portions where mucous cells of the glands produce mucins with terminal alpha1,4-GlcNAc O-glycans. This structure exerts antimicrobial activity against Hp. The development of IM in the stomach is characterized by Hp clearance from the metaplastic glands and by major alterations in the expression of mucins and mucin-carbohydrates. The present work evaluated whether terminal alpha1,4-GlcNAc and sialyl-Tn antigen are implicated in the process of Hp clearance from metaplastic glands by analyzing the expression of these antigens in different types of IM-complete (n=12) and incomplete (n=8)-and in gastric cell lines. Terminal alpha1,4-GlcNAc was not detected in IM except in a single foci of one case, indicating that this structure is not implicated in the clearance of Hp from IM, in contrast to what is observed in normal gastric mucosa. None of the gastric carcinoma cell lines studied showed terminal alpha1,4-GlcNAc, suggesting that they do not display a gastric gland mucous cell phenotype and therefore are useful models for in vitro Hp studies. Finally, sialyl-Tn antigen colocalizes with MUC2 mucin and is present in all cases of complete and incomplete IM, suggesting that either or both can be implicated in Hp clearance from IM.     

Expression of UDP-N-acetyl-D-galactosamine: polypeptide N-acetylgalactosaminyltransferase-6 in gastric mucosa, intestinal metaplasia, and gastric carcinoma

Aberrant mucin O-glycosylation is often observed in cancer and is characterized by the expression of immature simple mucin-type carbohydrate antigens. UDP-N-acetyl-d-galactosamine:polypeptide N-acetylgalactosaminyltransferase-6 (ppGalNAc-T6) is one of the enzymes responsible for the initial step in O-glycosylation. This study evaluated the expression of ppGalNAc-T6 in human gastric mucosa, intestinal metaplasia, and gastric carcinomas. Our results showed that ppGalNAc-T6 is expressed in normal gastric mucosa and in intestinal metaplasia. A heterogeneous expression and staining pattern for this enzyme was observed in gastric carcinomas. ppGalNAc-T6 was expressed in 79% of the cases, and its expression level was associated with the presence of venous invasion. Our results provide evidence that ppGalNAc-T6 is an IHC marker associated with venous invasion in gastric carcinoma and may contribute to the understanding of the molecular mechanisms that underlie aberrant glycosylation in gastric carcinogenesis and in gastric carcinoma.