Achylia, pernicious anaemia, ECL cells and gastric carcinoids

The central role of gastrin in Helicobacter pylori gastric carcinogenesis

Gastric cancer is still a prevalent and lethal cancer. Gastric hypoacidity and gastritis have long been recognized in the pathogenesis. The identification of Helicobacter(H.) pylori as the main cause of gastritis leading to peptic ulcer disease and gastric cancer was a breakthrough. H. pylori was the first bacterium accepted as a carcinogen. The mechanism was not found before H. pylori was shown to predispose to cancer only after having induced oxyntic atrophy incriminating reduced killing of microorganisms and/or secondary hypergastrinemia. H. pylori has an uncertain carcinogenic role in cardia cancer, making microbes more unlikely. Gastrin has a trophic effect on the oxyntic mucosa, particularly on the enterochromaffin like cell carrying the gastrin receptor. Every condition with long-term hypergastrinemia in whatever species predisposes to gastric neoplasia. All observations on gastric neoplasia connected to H. pylori gastritis (the protective effect of duodenal ulcer, increased risk with oxyntic atrophy and preserved risk after loss of H. pylori in complete oxyntic atrophy) may be explained by gastrin. The role of gastrin in gastric carcinogenesis is also reflected by autoimmune gastritis and profound long-term gastric acid inhibition.

Correctly identifying the cells of origin is essential for tailoring treatment and understanding the emergence of cancer stem cells and late metastases

Malignancy manifests itself by deregulated growth and the ability to invade surrounding tissues or metastasize to other organs. These properties are due to genetic and/or epigenetic changes, most often mutations. Many aspects of carcinogenesis are known, but the cell of origin has been insufficiently focused on, which is unfortunate since the regulation of its growth is essential to understand the carcinogenic process and guide treatment. Similarly, the concept of cancer stem cells as cells having the ability to stop proliferation and rest in a state of dormancy and being resistant to cytotoxic drugs before "waking up" and become a highly malignant tumor recurrence, is not fully understood. Some tumors may recur after decades, a phenomenon probably also connected to cancer stem cells. The present review shows that many of these questions are related to the cell of origin as differentiated cells being long-term stimulated to proliferation.

Inflammation and Digestive Cancer

Chronic inflammation is linked to carcinogenesis, particularly in the digestive organs, i.e., the stomach, colon, and liver. The mechanism of this effect has, however, only partly been focused on. In this review, we focus on different forms of chronic hepatitis, chronic inflammatory bowel disease, and chronic gastritis, conditions predisposing individuals to the development of malignancy. Chronic inflammation may cause malignancy because (1) the cause of the chronic inflammation is itself genotoxic, (2) substances released from the inflammatory cells may be genotoxic, (3) the cell death induced by the inflammation induces a compensatory increase in proliferation with an inherent risk of mutation, (4) changes in cell composition due to inflammation may modify function, resulting in hormonal disturbances affecting cellular proliferation. The present review focuses on chronic gastritis (Helicobacter pylori or autoimmune type) since all four mechanisms may be relevant to this condition. Genotoxicity due to the hepatitis B virus is an important factor in hepatocellular cancer and viral infection can similarly be central in the etiology and malignancy of inflammatory bowel diseases. Helicobacter pylori (H. pylori) is the dominating cause of chronic gastritis and has not been shown to be genotoxic, so its carcinogenic effect is most probably due to the induction of atrophic oxyntic gastritis leading to hypergastrinemia.

Correct Identification of Cell of Origin May Explain Many Aspects of Cancer: The Role of Neuroendocrine Cells as Exemplified from the Stomach

Cancers are believed to originate from stem cells. Previously, the hypothesis was that tumors developed due to dedifferentiation of mature cells. We studied the regulation of gastric acid secretion and showed that gastrin through the gastrin receptor stimulates enterochromaffin-like (ECL) cell histamine release and proliferation. In animal and human studies, we and others showed that long-term hypergastrinemia results in ECL cell-derived tumor through a sequence of hyperplasia, dysplasia, neuroendocrine tumors (NETs), and possibly neuroendocrine carcinomas (NECs) and adenocarcinomas of diffuse type. Perhaps, other cancers may also have their origin in differentiated cells. Knowledge of the growth regulation of the cell of origin is important in cancer prophylaxis and treatment. Physiology plays a central role in carcinogenesis through hormones and other growth factors. Every cell division implies a small risk of mutation; thus mitogens are also mutagens. Moreover, metastasis of slow proliferating cells may also explain so-called tumor dormancy and late recurrence.

Clinical consequences of controversies in gastric physiology

Studies on the regulation of gastric acid secretion started more than 100 years ago at an early phase of experimental physiology. In nearly the whole last century there were disputes about the interpretation of the findings: the interaction between the three principle gastric acid secretagogues acetylcholine, gastrin and histamine, the cell producing the relevant histamine which turned out to be the ECL cell, the ability of the ECL cell to divide and thus develop into tumours, the classification of gastric carcinomas and the mechanism for Helicobacter pylori carcinogenesis. The elucidation of the central role of the ECL cell and thus its main regulator, gastrin, solve all these controversies, and gives a solid base for handling upper gastrointestinal diseases.

Nonantral gastric carcinoid tumours associated with hypergastrinaemia

Nonantral gastric carcinoid tumours in association with pronounced hypergastrinaemia are reported in 6 patients. It is suggested that the hypergastrinaemia, as a result of lack of a negative acid feedback inhibition in an achlorhydric stomach, promoted the tumour development, possibly initiated by action of carcinogenic nitrosamines, in the gastric juice.

Regression of type II gastric carcinoids in multiple endocrine neoplasia type 1 patients with Zollinger-Ellison syndrome after surgical excision of all gastrinomas

Enterochromaffin-like (ECL) tumors are documented in patients with hypergastrinemia secondary to chronic atrophic gastritis or with Zollinger-Ellison syndrome and multiple endocrine neoplasia type 1 (ZES-MEN-1). In patients with ECL tumors and atrophic gastritis, normogastrinemia after antrectomy has resulted in resolution, regression, or stabilization of ECL tumors. The natural history of ECL tumors associated with ZES-MEN-1 following normalization of gastrin levels after gastrinoma resection has not been previously reported. The purpose of this study was to determine the course of ECL tumors in patients with ZES-MEN-1 following normalization of serum gastrin levels after gastrinoma resection. Two patients with ZES-MEN-1 had biopsy-proven ECL tumors on endoscopic evaluation. They then underwent surgical exploration that included distal pancreatectomy, enucleation of pancreatic head tumors, duodenotomy with excision of submucosal tumors, and peripancreatic lymphadenectomy. Gastric ECL tumors larger than 1.0 cm were locally excised. Patients underwent long-term follow-up with biochemical and endoscopic surveillance. Normogastrinemia was achieved and sustained following gastrinoma resection in two patients with ZES-MEN-1. Periodic endoscopic surveillance over a 6-year period showed complete resolution of the ECL tumors. The development of ECL tumors associated with ZES-MEN-1 is multifactorial. Studies identified a genetic influence on tumor growth with loss of heterozygosity at the MEN-1 gene locus in ECL tumors. The resolution of ECL tumors in ZES-MEN-1 patients who are normogastrinemic indicates that an elevated gastrin level is a primary initiator for development of these tumors. Therefore both genetic defects and hypergastrinemia are causative agents. Normalization of serum gastrin levels is critical for the prevention of aggressive forms of ECL tumors.

Gastric carcinoids: a statistical evaluation of 1,094 cases collected from the literature

Gastric carcinoids are a rare gut endocrinoma, and only a few series dealing with limited aspects have been published. This study evaluates the present status and characteristics of gastric carcinoids in a statistically reliable series of 1,094 cases that were carefully evaluated, computerized, and analyzed by the "Gut-Pancreatic Endocrinoma Analyzing System." Routine statistical analysis was carried out on 1,011 patients, excluding 83 with atypical carcinoids, focusing on clinical manifestations, location, depth, and size of the lesions in relation to metastases, immunohistochemistry, carcinoid syndrome, serotonin activity, electron microscopy, multicarcinoid complex with type A gastritis, and postoperative outcome. A tumor size of 20 mm or less comprised 60.8% of the series, with a metastasis rate of 15.1%, and depth of invasion to the submucosa occupied 53.8%, with a metastasis rate of 13.2%. Carcinoid syndrome was encountered in 4.0% of the patients. Elevated serotonin activity was detected in 22.3% overall and in 67.7% of the patients with carcinoid syndrome (P < 0.01). Multicarcinoid complex with type A gastritis was detected in 140 of 347 patients with multicarcinoid complex, and 97.1% had associated lesions in the nonantral regions of the stomach. A comparative evaluation between patients with and without type A gastritis indicated a number of significant differences including male to female ratio, age distribution, location, tumor size, depth of invasion, metastasis, and prognosis.

Trophic effects of gastrin

Gastrin is an important trophic hormone for the acid-producing part of the stomach. There is no solid evidence that gastrin is physiologically important as a trophic agent outside the stomach. The trophic effects in the stomach are manifested as an increased weight and thickness of the oxyntic mucosa and can be induced by both exogenous and endogenous gastrin--that is, in situations of long-lasting hypergastrinemia (treatment with effective antisecretagogues, partial fundectomy, or antrum exclusion). Removal of endogenous gastrin by antrectomy induces the opposite effects--that is, diminished weight and thickness of the oxyntic mucosa. Unlike all other peptide hormone-producing endocrine cells in the oxyntic mucosa, the so-called enterochromaffin-like (ECL) cells respond readily to gastrin. An acute gastrin challenge results in release of stored products from the ECL cells (such as histamine) and activation of cytoplasmic enzymes (such as histidine decarboxylase). Sustained elevation of circulating gastrin over days results in hypertrophy of the ECL cells and over weeks results in marked hyperplasia (at most a fivefold increase in the rat). The results in other species are similar but often somewhat less marked than in the rat.

Serum gastrin concentration affects the self replication rate of the enterochromaffin like cells in the rat stomach

The influence of antrectomy and antrum exclusion on the enterochromaffin like cell kinetics in the gastric mucosa of the rat was studied using a combination of histamine immunocytochemistry and autoradiography after in vivo labelling with tritiated thymidine. In all experimental groups, the enterochromaffin like cells were found to incorporate the DNA precursor, thus indicating an ability to divide. The serum gastrin concentration was raised by antrum exclusion and reduced by antrectomy. After antrum exclusion, the enterochromaffin like cell proliferation rate increased as indicated by a doubling of the labelling index and by the resulting enterochromaffin like cell hyperplasia (after six weeks). After antrectomy, the enterochromaffin like cell labelling index decreased to reach 25% of the control value; at this time the enterochromaffin like cell density had not decreased significantly. The observed correlation between the enterochromaffin like cell labelling indices and the serum gastrin concentration supports the hypothesis that enterochromaffin like cell proliferation is influenced by serum gastrin.

Potential hazards of long-term acid suppression

Neuroendocrine cell (carcinoid) tumours have been reported in the acid-secreting part of the stomach of rodents after long-term administration of a range of potent chemically diverse antisecretory agents. Although evidence shows a link between the sequence of acid suppression, hypergastrinaemia, and neuroendocrine cell hyperplasia, other factors are also thought to be involved in neoplastic transformation. Prolonged hypochlorhydria or achlorhydria resulting in bacterial colonization of the stomach may allow the generation of carcinogenic substances. Other as yet unidentified trophic factors may be involved in tumour formation. In view of the potential risks associated with these agents, there must be concern about the possible consequences in man of marked suppression of acid. It seems wise to limit the use of these more potent agents to situations in which conventional therapy has failed and to short-term treatment.

Gastrointestinal carcinoid tumours. Histogenetic, histochemical, immunohistochemical, clinical and therapeutic aspects

The increased knowledge of the pathobiology of gastrointestinal carcinoid (neuroendocrine) tumours and the improved therapeutic possibilities have brought a demand for more precise diagnosis. Although the carcinoid tumours can often be tentatively recognized in routinely processed microscopic slides, their more accurate identification requires additional diagnostic procedures. General neuroendocrine markers such as the argyrophil reaction of Grimelius and immunohistochemistry with application of antibodies against chromogranin A and of neuron-specific enolase are discriminatory staining methods which are used to reveal the neuroendocrine origin of almost all highly differentiated carcinoid tumours of the gastrointestinal tract. Mid-gut carcinoids, which predominate among these tumours almost unexceptionally contain serotonin. This biogenic amine can be demonstrated by the argentaffin reaction of Masson, serotonin immunoreactively or by formalin-induced fluorescence. The characteristic staining pattern of mid-gut carcinoids is almost invariably preserved in the metastatic deposits and consequently the staining methods for identifying serotonin can also be used on metastases to reveal a primary mid-gut carcinoid. The enterochromaffin-like (ECL) cell carcinoids of the body and fundic area of the stomach often seen in association with pernicious anaemia are argyrophil with the Sevier-Munger silver stain. Other neuroendocrine tumours, viz. antral, duodenal and rectal carcinoids should be studied by a battery of relevant peptide hormone antisera for adequate diagnosis. During the last decade new peptide hormones have been found in circulation in patients with carcinoid tumours, but serotonin and urinary 5-HIAA are still the most important markers for carcinoids of the mid-gut origin. Other clinically useful tumour markers are chromogranin A + B, pancreatic polypeptide, human chorionic gonadotropin alpha and beta subunits. For localizing procedures, angiography is the most reliable investigative method for primary tumours in the gut, whereas CT-scan and ultrasound investigations are good for detection of liver metastases. During the last five years, the therapy for malignant carcinoid tumours has been considerably improved. Chemotherapy has only revealed objective response rates in about 10-30% of the patients giving median survivals from start of therapy of about 10 months. Recently treatment with alpha interferons and the new somatostatin analogue octreotide have given objective responses in 50-75% of patients with malignant mid-gut carcinoid tumours. These patients have now a median survival from start of therapy of 70 months when treated with alpha interferons. In the future new therapies will come into use such as monoclonal antibodies and perhaps also agents blocking different growth factors.

A case of multiple carcinoid tumors of the rectum with extraglandular endocrine cell proliferation

A case of multiple carcinoid tumors of the rectum with numerous proliferations of extraglandular endocrine cells is reported. The patient was 52-year-old man with five polypoid lesions in the rectum. The resected rectum contained five macroscopic carcinoid tumors, 36 microcarcinoids, and innumerous extraglandular endocrine cell proliferations. Endocrine cell microproliferations, in their early stage consisting of one to 15 micronests, were mainly located within the bundles of muscularis mucosae, having no contact with mucosal glandular structures. All of the immunohistochemically examined proliferations of extraglandular endocrine cells contained S-100 protein-positive dendritic cells, and some endocrine cells coexisted with submucosal ganglion cells. In contrast, there was no increase in intraglandular endocrine cells. The origin of rectal carcinoid tumor may be the extraglandular endocrine cells, a distinct compartment of mucosal endocrine cells of the rectum.

Gastric carcinoid tumors, endocrine cell hyperplasia, and associated intestinal metaplasia. Histologic, histochemical, and immunohistochemical findings

Eleven cases of gastric carcinoid tumor have been studied to review their clinical and pathologic spectrum, to identify any relationship to pernicious anemia, and to evaluate the accompanying gastric mucosal changes, with particular reference to the endocrine cell population. Seven patients were male and four female; ages ranged from 26 to 83 years. Two male patients had documented pernicious anemia and one female patient had unconfirmed pernicious anemia. All patients had marked gastric intestinal metaplasia (atrophic gastritis), which was predominantly fundal (Type A) in three patients with suspected/proven pernicious anemia and antral (Type B) in the other eight. In seven patients, the tumors were typical carcinoids, whereas in 4 patients the carcinoids were "atypical"; one carcinoid was completely polypoid. All cases were argyrophilic, and focal mucin positivity was present in four. Focal somatostatin immunoreactivity was present in four cases, serotonin in three cases, vasoactive intestinal polypeptide (VIP) in two cases, and gastrin (G) in one case. Endocrine cell hyperplasia was identified in the gastric mucosa of eight of 11 patients, including all cases with pernicious anemia; in three of eight cases, G-cell hyperplasia was evident. Numbers of serotonin-positive cells were increased in areas of intestinal metaplasia in all cases. In two patients, there was marked endocrine-cell hyperplasia with multiple small carcinoid tumorlets; the tumorlets stained for G in one. Gastric intestinal metaplasia includes intestinal-like endocrine cells. An association exists between atrophic gastritis and gastric carcinoids, and there is a histogenetic link between atrophic gastritis and some cases of gastric carcinoid tumor.

Nuclear DNA recordings in gastric carcinoids. A cytofluorometric study on single tumour cells

Cytofluorometric nuclear DNA analyses were performed on single tumour cells from eight argyrophilic gastric carcinoids. Three tumours displayed grossly diploid DNA values, with a fraction of S-phase cells of 1-8%. Four other tumours were also mainly diploid, but showed an increased number of tetraploid cells, and one tumour was aneuploid with a stem-cell line of triploid cells. These and previous results indicate that gastric carcinoids are relatively heterogenous with respect to their morphology, nuclear DNA profiles and biological behaviour, in contrast to most intestinal "classical" carcinoids. Furthermore, the results are in accordance with the suggestion that gastric carcinoids may represent a highly differentiated variety within a spectrum of neuroendocrine neoplasia analogous to the corresponding variety observed in the bronchus (carcinoid-small cell, undifferentiated carcinoma).

Subepithelial neuroendocrine cells and carcinoid tumours of the human small intestine and appendix. A comparative immunohistochemical study with regard to serotonin, neuron-specific enolase and S-100 protein reactivity

A comparative immunocytochemical study was performed of subepithelial neuroendocrine cells of the human small intestine and appendix and carcinoid tumours of these sites, using a monoclonal antibody to serotonin and polyclonal antisera against neuron-specific enolase (NSE) and S-100 protein. Subepithelial neuroendocrine cells were easily identified in the lamina propria of the appendix. These cells, which sometimes occurred in aggregates, displayed serotonin and NSE immunoreactivity and were surrounded by S-100 protein immunoreactive cells, presumably of Schwann cell origin. In the appendix scattered cells with corresponding morphological features and immunoreactivity were also observed deep in the submucosa. In addition, subepithelial neuroendocrine cells were sparsely present in the lamina propria of the small intestine, occurring only as single cells in the deeper part of the mucosa below or between the epithelial crypts. Most appendiceal carcinoid tumours (11 of 12 examined cases) were biphasic and consisted of neuroendocrine tumour cells with intermingled S-100 protein immunoreactive cells (Schwann cells) with long cytoplasmic extensions. However, small intestinal (11 cases) and caecal (10 cases) carcinoids lacked S-100 protein immunoreactive cells as an integral component. The results indicate that the appendiceal carcinoids are mostly closely related structurally to the subepithelial neuroendocrine and Schwann cell aggregates of the lamina propria and are thus presumed to be histogenetically related to this cell system, while the histogenesis of small-intestinal and caecal carcinoids remains less clear.

Gastrin and the trophic control of gastric mucosa

Gastrin is a trophic stimulant of the acid producing gastric mucosa. Experiments have been carried out in rats, in which chronic states of either low or high serum gastrin levels were induced by surgical manipulation or drug treatment. A relationship between circulating gastrin and a trophic effect could be demonstrated in the oxyntic mucosa, but not in the pancreas and small intestine. Endocrine cells in the oxyntic mucosa (the ECL cells and A-like cells) are among the target cells for the trophic action of gastrin. The functional significance of these two cell populations is unknown. There is much experimental evidence indicating that they are under functional as well as tropic control of gastrin. The vagus nerve also exerts trophic control on the oxyntic mucosa, including the endocrine cells within it. This could be demonstrated by one-sided truncal vagotomy which caused atrophy of the mucosa and hypoplasia of endocrine cells (notably the ECL cells) on the denervated side of the stomach. Conversely, portacaval shunt greatly increased the number of ECL cells. There was no hypergastrinaemia after portacaval shunt, and no trophic effect on other cell types in the oxyntic mucosa. The factors responsible for the ECL cell proliferation after portacaval shunting remain unknown. Tumours may arise spontaneously from the ECL cells. Such neoplasias have been described in Mastomys (Praomys natalensis) and in man. ECL cell hyperplasia and neoplasia in man, but not in Mastomys, are usually associated with hypergastrinaemia either as a result of a gastrin producing tumour or as a result of achylia (sometimes associated with pernicious anaemia). It is unlikely that gastrin alone is responsible for the neoplasia, though it is quite likely that long-standing hypergastrinaemia triggers or facilitates a sequence of events that ultimately leads to tumour formation, via diffuse ECL cell hyperplasia.

The prevalence, prognostic significance and hormonal content of endocrine cells in gastric cancer

Twenty-six of 100 cases of gastric adenocarcinoma contained argyrophil cells. All these tumours were carcino-embryonic antigen positive and 13 contained variable amounts of gastro-enteropancreatic peptides and amines. There was no significant difference in mucin type, extent or incidence of intestinal metaplasia between tumours with and those without endocrine cells. The prognosis for both groups was similarly poor, contrasting with that for carcinoid and atypical carcinoid. Endocrine cell hyperplasia was evident in the adjacent mucosa in some of the cases of endocrine positive tumours. There was no association between achlorhydria and the presence of endocrine cells in the tumours. The origin of the neoplastic endocrine cells remains speculative, occurring either as a mutation of a single stem cell or as a synchronous malignant transformation of two epithelial cell types exposed to a particular carcinogenic factor(s). Adenocarcinomas containing endocrine cells appear to be as biologically aggressive as the usual adenocarcinomas of the stomach and therefore should be treated in a like manner.

What's new in endocrine factors of tumor growth?

In this review some aspects of endocrinological factors in cancer are discussed. The first part addresses the determination of steroid hormone receptors in cancer of the breast. The importance of steroid hormone receptor determination for the clinical management of breast cancer patients is emphasized. Current methods for receptor measurement are critically evaluated and it is concluded that rigorous standardization of tissue handling procedures and of radiochemical methodology is mandatory to improve the reliability of the presently available methods. The development of new techniques for receptor determination has been met with high expectations. Monoclonal antireceptor antibodies in principle allow the development of a radioimmunoassay but are not widely available as yet. Histochemical methods for receptor localization have so far failed to meet accepted criteria of specificity. Therefore radiochemical determination at present remains the only reliable method. The second part addresses the production of peptide hormones by endocrine tumours of the gastroenteropancreatic (GEP) system and by non-neuroendocrine neoplasms. In the endocrine tumours of the GEP system a wide range of peptide hormones can be detected by immunocytochemistry, but most frequently the pattern of hormone production is comparable with that in the normal organ of origin. Clinical symptoms of excess hormone production occur much less frequently than hormone production is found by immunological methods and is usually caused by one hormone. It is proposed that these neoplasms are classified according to the hormone which causes the leading clinical symptoms and/or the hormone with the highest serum level. Peptide hormone producing cells in classical carcinoma are an intriguing phenomenon which has shed some new light on the embryological origin of neuroendocrine cells in the relevant organs and also on the histogenesis of neuroendocrine as well as non-neuroendocrine neoplasms.

Multifocal gastric carcinoid tumours, achlorhydria, and hypergastrinaemia

Multiple polypoidal carcinoid tumours of the stomach were found in 5 patients with achlorhydria (4 of whom had pernicious anaemia) as a result of autoimmune atrophic gastritis. The tumours were small (nearly all less than 1 cm diameter) and appeared to grow very slowly, if at all; no significant enlargement or complications were seen during periods of observation of up to 6 years. No extragastric hormonal syndromes were identified. They differed from the carcinoid tumours usually found in the intestinal tract by being composed of argyrophil (not argentaffin) cells of the enterochromaffin-like (ECL) type. Fasting plasma levels of gastrin, which is believed to be trophic to ECL cells, were very high in all patients. Thus, chronic hyperplasia of gastric ECL cells (as a result of hypergastrinaemia) may have been responsible for development of the tumours. Long-term, uninterrupted achlorhydria produced by potent inhibitors of gastric acid secretion might therefore predispose to carcinoid tumours of the stomach.

Histopathology of gastric carcinoids: a survey of 42 cases

An unselected series of 42 gastric carcinoids has been reviewed. Clinically the tumours simulated common gastric lesions including ulcer, polyp and carcinoma. No endocrine symptoms were identified. The tumours were most frequent in the body of the stomach and in 25% in that site were multiple. Morphologically most tumours when classified according to Soga (1974) demonstrated a mixed growth pattern. Six tumours displayed an atypical morphology (type D): they were larger and metastasized more frequently than the rest of the tumours. Six tumours contained a few scattered argentaffinic cells but the others were negative indicating negligible serotonin secretion in only a few cases. The Grimelius argyrophilic reaction was positive in most cells in all tested tumours except in three, two of which showed atypical morphology (type D). It is suggested that gastric carcinoids with a type D morphology or a minority cell population of argyrophil cells are dedifferentiated carcinoids which are biologically nearer to gastric carcinomas. The most frequent clinicopathological correlation was achlorhydria linking pernicious anaemia and gastric carcinoids. This indicates pathogenetic similarities between gastric carcinoids and gastric carcinomas.

Gastroscopic screening in 80 patients with pernicious anaemia

We have studied 80 patients with pernicious anaemia. Upper gastrointestinal endoscopy (with biopsy and cytology) showed no lesion other than atrophic gastritis in 34 patients. Thirty three patients, however, had varying degrees of gastric mucosal dysplasia, which was detected more frequently by histology than by cytology. The endoscopic appearance of the mucosa was abnormal in four of the six patients with moderate dysplasia, and in all three patients with severe dysplasia. One patient was found to have a small carcinoma in the gastric antrum, and underwent total gastrectomy; 18 patients had polyps (often multiple); four of these were treated by endoscopic polypectomy. One of the patients with polyps had multiple carcinoid tumours, and an asymptomatic parathyroid adenoma. Seventeen of the patients also underwent barium meal examination; abnormalities were revealed in only three of the seven patients with lesions visible at endoscopy. Our results justify further endoscopic studies in patients with pernicious anaemia, and sequential examinations to establish the natural history of gastric dysplasia.

Neurohormonal peptides in endocrine tumors of the pancreas, stomach, and upper small intestine: I. An immunohistochemical study of 27 cases

Preliminary observations have indicated the existence of characteristic spectra of gastroenteropancreatic (GEP) neurohormonal peptides in endocrine tumors arising in foregut, midgut, and hindgut derivatives. In order to further explore this feature of GEP endocrine neoplasms, islet cell tumors from 14 patients were studied, as were endocrine tumors of the stomach, duodenum, and upper jejunum from 6, 5, and 2 patients, respectively. All tumors were examined immunohistochemically with antisera raised against islet hormones [insulin, somatostatin, glucagon, pancreatic polypeptide (PP)], peptides of the gastrin family [gastrin, cholecystokinin (CCK)], peptides of the secretin family [secretin, vasoactive intestinal peptide (VIP)], and substance P, neurotensin, leu-enkephalin, beta-endorphin, motilin, calcitonin, and ACTH. In addition, an ultrastructural investigation was made. Whenever possible, the immunohistochemical observations were correlated with the clinical manifestations and with the results of radioimmunochemical determination of GEP neurohormones in the blood. The pattern of immunoreactive neurohormonal peptides and the clinical picture were those to be expected in endocrine tumors arising in foregut derivatives. Some principles are proposed for the classification of GEP endocrine tumors on the basis of their histopathologic growth pattern, their spectrum of neurohormonal peptides, and their clinical manifestations.

A clinical study of 30 gastric carcinoids

The clinical picture in 30 patients operated on for gastric carcinoids was studied retrospectively. There were 12 men and 18 women, with an age range of 32-79 years (mean 57 years). The tumours were located in the corpus area of the stomach in more than half of the patients and in one-third were relatively small (less than or equal to 1 cm). Four patients had multiple tumours. Metastases were found in eight patients, mostly those with larger primary tumours. In no case was the carcinoid syndrome present. The patients presented symptoms simulating those of more common affections of the stomach, such as polyps, ulcer and carcinoma. Barium contrast study and gastroscopy did not reveal the true nature of the gastric disease and even biopsy of the stomach failed to give a correct preoperative diagnosis in four of five patients. Since six patients had achylia preoperatively, it is emphasized that the possibility of a gastric carcinoid, especially in the corpus area, is more likely in association with this condition.

Achylia and the development of gastric carcinoids

Twenty-four patients with gastric carcinoids were examined retrospectively with regard to the presence of achylia and pernicious anaemia (PA). Six patients (25%) had achylia preoperatively and half of these had an associated PA. The gastric carcinoids occurring in an achylic stomach were almost exclusively located to the corpus area and tended to be multiple. Further, the majority of cells in most of them were argyrophil (Sevier-Munger) positive, indicating that they were of the enterochromaffin-like cell type. At present, achylia with or without concomitant PA appears to be the most distinct condition associated with gastric carcinoids. The pathogenesis of these tumours which develop in an achylic stomach is discussed.