Purification of human intestinal goblet cell antigen (GOA), its immunohistological demonstration in the intestine and in mucus producing gastrointestinal adenocarcinomas

Colonic epithelium reactive monoclonal antibodies. Identification and immunohistochemical localization of the target epitopes

We have produced a small library of colonic mucosa and colorectal carcinoma reactive monoclonal antibodies (MoAbs) by immunizations with extracts of human colon cancer tissue and a human colon cancer cell line. Hybridoma supernatants were tested on (normal and neoplastic) human tissues by immunoperoxidase methods to evaluate organ or tissue specificity. Initial biochemical characterization of the target antigens was performed by gelpermeation chromatography, Western blotting and competition assays. Based upon the immunoreactivity patterns and the characteristics of the antigen four groups of MoAbs could be distinguished. The first group concerns the antibodies PARLAM 3, 9 and 10. These antibodies react with an 87 kDa protein moiety in high molecular weight (2-5 x 10(6) Da) glycoproteins. In intestinal and colon mucosa these antibodies showed diffuse binding with goblet cells. In colon carcinoma decreased reactivity with these MoAbs was found. The second group consists of antibodies PARLAM 8, 12 and 13. These antibodies react with large (greater than 5 x 10(6) Da) glycoproteins, most likely with carbohydrate epitopes. By immunohistochemistry in normal colon mucosa the antibodies all show granular supranuclear reactivity with goblet cells. These antibodies show increased reactivity with colon adenomas and adenocarcinomas. A third group is formed by PARLAM 2, which also reacts with a large (greater than 5 x 10(6) Da) glycoprotein, showing a granular distribution in goblet cells. In colon carcinomas more extensive expression is found than in normal colonic mucosa. Finally, the fourth group consists of PARLAM 11, which also reacts with a large (greater than 5 x 10(6) Da) glycoprotein, located in the brush border of colonic columnar cells. These antibodies might be useful tools for the analysis of the expression of mucin related glycoproteins in normal, preneoplastic and neoplastic colon mucosa.

Widespread expression of intestinal markers in gastric carcinoma: a light and electron microscopic study using BD-5 monoclonal antibody

BD-5 monoclonal antibody reacted with tumour cells in 262 of 316 cases of gastric cancers, including 121 of 134 early, 141 of 182 advanced tumours (p less than 0.01), and 113 of 146 glandular, 72 of 83 diffuse, 22 of 25 mucoid, and 55 of 59 mixed tumours. No difference in reactivity was observed between metastatic and non-metastatic advanced tumours. Immunocytochemical techniques applied to light and electron microscopical specimens of colorectal mucosa and gastric cancer showed that BD-5 immunoreactive material occurred in the Golgi complex, in small clear, to dense cored, cytoplasmic vesicles, and in the glycocalix of the luminal and lateral membranes of normal and neoplastic cells in the glands, as well as in the peripheral membrane of dispersed neoplastic cells. Mucin granules stored in the cytoplasm of goblet cells were unreactive or poorly reactive. Ultrastructural features consistent with colorectal type differentiation were observed in many reactive tumours. Unreactive tumours showing ultrastructural patterns consistent with intestinal differentiation, especially of small bowel type, were also observed. Signs of intestinal differentiation, including BD-5 immunoreactivity, often occur in gastric cancer, irrespective of histological type and stage of disease.

Signet-ring cells in advanced gastric cancer. A clinical, pathological and histochemical study

A pathological and histochemical study on the presence of signet-ring cells (SRC) in 108 advanced gastric cancer (AGC) has been evaluated. According to Laurén's classification, 59 were of intestinal (I) and 49 of diffuse (D) type. The amount of SRC seems to be a prognostic parameter in D-carcinoma: the 5-year survival rate was 49% and 22% in cases with 1-24% and 75-100% SRC, respectively. Histochemically, in our series of SRC D-carcinoma the quality of mucin secretion of SRC closely resembled the goblet cells of intestinal metaplasia. The histogenetic origin of D-gastric carcinoma was discussed.

An immunohistochemical study of a colonic mucus antigen in normal and neoplastic gastrointestinal tissues

A monoclonal antibody YPC 44.3 which reacts with human large intestinal goblet cell mucus has been used to examine normal gastrointestinal mucosa and a series of gastric and colorectal carcinomas in an immunohistochemical study. In normal colonic mucosa the antibody is shown to detect an antigen which is expressed polymorphically and depends on the presence of the active allele at the Lewis locus for its expression. However the antigen appears distinct from regular Lewis antigens on the basis of immunoabsorption studies and organ distribution. Results of immunostaining tumours show no correlation with the site, classification or grade of tumour or the type of metaplasia adjacent to gastric cancers. The relationship of YPC 44.3 to other mucus antibodies and the importance of screening tissues with a wide range of blood group phenotypes is discussed.

Colonic and gastric mucus-associated antigens: a comparative immunohistological study in precancerous and cancerous rat intestinal mucosa

Gastric M1 antigens were previously shown to be oncofetal markers for the colon in man and in the rat. They were observed very early during carcinogenesis in goblet cells of precancerous colonic mucosa; using an immunohistological method, we found that M1 were produced in 68% (41/60) of colonic adenocarcinomas and in 33% (21/63) of duodenal adenocarcinomas. M3C antigen has been described as being associated with human colonic mucus; in the rat it is restricted to the proximal colon. We found that M3C was produced in 91% (55/60) of colonic adenocarcinomas and in 15% (8/53) of duodenal adenocarcinomas. Before tumor appearance, M3C was sometimes expressed by goblet cells of the distal colon. We could not find it during fetal life. We have concluded that mucus-associated antigens can characterize modifications in cell differentiation in rat colonic carcinomas.

Purification and characterization of a pancreatic cancer-associated antigen (PCAA) from normal colonic mucosa

The same antigenic substance as pancreatic cancer-associated antigen (PCAA), sharing an identical immunogenicity with Gelder's POA, was isolated and purified from normal colonic mucosa. Purified colonic PCAA (PCAAc) is a glycoprotein with a molecular weight of approximately 600,000; it consists of 30% carbohydrates and 70% peptides, and appears to be an N-glycosidic glycoprotein. Antiserum raised against purified PCAAc showed one fused line with our original anti-PCAA antiserum to ascites fluid from patients with pancreatic cancer and extract from normal colonic mucosa. Circulating PCAAc levels assayed by rocket immunoelectrophoresis showed significant elevation in sera of patients with carcinoma of the pancreas. It is concluded that PCAA might be a new tumor-associated antigen which is produced ectopically during oncogenesis.

Lectin--peroxidase conjugates in histopathology of gastrointestinal mucosa

Peroxidase (HRP) conjugates of Dolichos biflorus agglutinin (DBA), Arachis hypogaea agglutinin (PNA) and Ulex europaeus agglutinin I (UEA I) were used as specific molecular probes in order to describe histological patterns of carbohydrate moieties in glycoconjugates of gastric mucosa. Specimens of normal mucosa, metaplasias and carcinomas were fixed, embedded in paraffin and stained with lectins by a postembedding technique. In normal mucosa, DBA reacted with surface epithelial, parietal and antral gland cells; neck cells did not react. In single goblet cell metaplasia, with few exceptions, goblet cells showed DBA binding. In contrast, mainly negative goblet cells were seen in intestinal metaplasia. In gastric carcinomas of intestinal or diffuse types, heterogeneous staining patterns were observed. Large numbers of mucus-producing surface epithelial, neck and antral gland cells stained with PNA-HRP conjugates. Parietal cells did not react. Among the chief cells only few showed PNA binding. In single goblet cell metaplasia, equal numbers of goblet cells were positive or negative, whereas goblet cells in intestinal metaplasia were mainly unstained. Carcinomas contained both PNA-positive and PNA-negative cells; PNA-positive cells occurred preferentially in the tumor periphery. UEA I - HRP conjugates stained the bulk of surface epithelial and neck cells; chief cells and antral gland cells were mainly positive, too. Parietal cells did not react. In single goblet cell metaplasia and intestinal metaplasia, UEA I-positive as well as UEA-negative goblet cells occurred. Striated cells exhibited a great variety of lectin reactivity. Carcinomas also showed a heterogeneous staining pattern. Under both normal conditions and in carcinoma development, qualitative and quantitative differences in the composition of glycoconjugates must be expected.

Minute gastric cancers less than 5 mm in diameter

Minute gastric cancers with maximum dimensions of less than 5 mm were studied clinicopathologically. There were 49 intramucosal cancers among 46 patients and nine submucosal cancers among nine patients. No lymph node metastasis was found. Macroscopically, eight (13.8%) were evaluated, 12 (20.7%) were flat, and 38 (65.5%) were depressed. Most submucosal cancers were of the depressed type (8/9, 88.9%). Classification of cancers according to association with other large cancers into single group (22 cases) and multiple group (33 cases) revealed that (1) the majority of the minute gastric cancers (20/22, 90.9%) in the single group were the depressed type and (2) submucosal cancers in the single group were 8/22, accounting for 36.4%, a much higher incidence as compared with 1/36 (2.9%) in the multiple group. These facts indicate that gastric cancers should be detected when they are about 5 mm in maximum dimension and before they invade beyond the submucosal layer, especially in single and depressed type.

Clinical aspects of gastrointestinal mucus

In such a bird's eye view of a very complicated and complex literature it is inevitable that significant contributions, particularly from earlier investigators, will have been overlooked. We have tried, however, to provide a reasonable framework for the many presentations and discussions which will take place at this conference. As in the past, it is evident that much needs to be done to reconcile the excellent histochemical studies of gastrointestinal mucus in many diseases with the increasing knowledge of mucin structure and composition. This will only be achieved by extraction of highly pure mucin from diseased bowel. In this regard, post mortem material provides an opportunity for mucin researchers which is not available to workers in other fields because of relative freedom from decomposition. The wedding of mucin technology with immunology is also a major priority. Immunoassay techniques provide the answer to quick and accurate product identification in secretion studies. Specific monoclonal antibodies will provide the route to structural differentiation of antigens in complex mixtures. It is also evident that we must seek to develop a variety of controllable models for the study of functional parameters of mucus in physiological conditions, parasite rejection, neoplasia and inflammatory states. Promising initiatives have been touched upon in this review, but these must only be the beginning. One must conclude, however, by recognizing that advances in knowledge have been truly remarkable since the last conference in 1976. One senses that some of the keys which will one day unlock the gates of this "ill-defined" kingdom are already in hand, while the remainder are at least within reach.

Intestinal M3 antigen, a marker for the intestinal-type differentiation of gastric carcinomas

The mucus-associated intestinal M3 antigen, normally restricted to intestinal goblet cells, was found in 35 out of 100 gastric adenocarcinomas belonging to intestinal (19/64) as well as diffuse (16/36) types according to Laurén's classification. often accompanying the other mucus-associated gastric M1 and M2 antigens. This M3 antigen was predominant over the gastric M antigens in 25 of these 35 tumors; 18 of these belonged to the histological intestinal type. According to the WHO classification, the M3 antigen was found to predominate in all mucinous adenocarcinomas (7/7), was never present in the undifferentiated carcinomas (0/8), but was also found in some tubulo-papillar (16/57) and signet-ring cell (12/27) adenocarcinomas. This antigen could be used as a new criterion and incorporated into a point system containing morphological and tumor cell behavioral considerations; then it would appear to be a good marker for intestinal-type differentiation. Indeed, 22 of these 25 gastric adenocarcinomas which produced predominantly M3 antigen showed such an intestinal-like differentiation. The M antigen pattern of gastric carcinoma suggested a duodenal rather than colonic-type differentiation.

Role of intestinal metaplasia in the histogenesis of gastric carcinoma

Recent evidence suggests that intestinal metaplasia (IM) cannot be regarded as a single entity. A simple classification of IM and its variants based on histological and mucin histochemical criteria was devised, and the incidence of IM subtypes in cancerous and benign gastrectomy specimens was recorded. A particular subtype was associated with 'intestinal' cancers but not with tumours considered to arise in normal gastric epithelium (P < 0.01) or with benign lesions (P < 0.01). This subtype appeared to lack absorptive cells at light microscopic level and secreted both neutral and acid mucins, including marked amounts of sulphomucin but no O-acetyl sialomucin.

Electron-microscopic study of the villous adenoma of the colon

The author studied the electron-microscopic peculiarities of villous adenoma as illustrated by 12 cases. She found that the dominant cells of villous adenoma are undifferentiated epithelial cells. Electron-microscopic signs of malignant transformation were revealed by nuclear changes, by the changes in the cytoplasmic membrane and by the immaturity of cells. Leuchtenberger's inclusion bodies are assumed to develop by herniation of cytoplasmic processes of immature tumour cells. In one tumour associated with electrolyte loss, atypical cells were observed with an electronmicroscopic picture indicative of an intense secretory activity. However, the secretion drops differed from the normal mucus drops of the mature goblet cells of the colonic mucosa. The author believes it to be possible that the tumour cells of atypical morphological appearance secrete mucus of abnormal composition which could be responsible for the syndrome of electrolyte loss.