Intestinal metaplasia of the regenerative epithelia in 549 gastric ulcers

Epistemology of the origin of cancer: a new paradigm

Background

Carcinogenesis is widely thought to originate from somatic mutations and an inhibition of growth suppressors, followed by cell proliferation, tissue invasion, and risk of metastasis. Fewer than 10% of all cancers are hereditary; the ratio in gastric (1%), colorectal (3-5%) and breast (8%) cancers is even less. Cancers caused by infection are thought to constitute some 15% of the non-hereditary cancers. Those remaining, 70 to 80%, are called “sporadic,” because they are essentially of unknown etiology. We propose a new paradigm for the origin of the majority of cancers.

Presentation of hypothesis

Our paradigm postulates that cancer originates following a sequence of events that include (1) a pathogenic stimulus (biological or chemical) followed by (2) chronic inflammation, from which develops (3) fibrosis with associated changes in the cellular microenvironment. From these changes a (4) pre-cancerous niche develops, which triggers the deployment of (5) a chronic stress escape strategy, and when this fails to resolve, (6) a transition of a normal cell to a cancer cell occurs. If we are correct, this paradigm would suggest that the majority of the findings in cancer genetics so far reported are either late events or are epiphenomena that occur after the appearance of the pre-cancerous niche.

Testing the hypothesis

If, based on experimental and clinical findings presented here, this hypothesis is plausible, then the majority of findings in the genetics of cancer so far reported in the literature are late events or epiphenomena that could have occurred after the development of a PCN. Our model would make clear the need to establish preventive measures long before a cancer becomes clinically apparent. Future research should focus on the intermediate steps of our proposed sequence of events, which will enhance our understanding of the nature of carcinogenesis. Findings on inflammation and fibrosis would be given their warranted importance, with research in anticancer therapies focusing on suppressing the PCN state with very early intervention to detect and quantify any subclinical inflammatory change and to treat all levels of chronic inflammation and prevent fibrotic changes, and so avoid the transition from a normal cell to a cancer cell.

Implication of the hypothesis

The paradigm proposed here, if proven, spells out a sequence of steps, one or more of which could be interdicted or modulated early in carcinogenesis to prevent or, at a minimum, slow down the progression of many cancers.

Relation between bile acid reflux into the stomach and the risk of atrophic gastritis and intestinal metaplasia: a multicenter study of 2283 cases

BACKGROUND

The relationship between bile acid reflux into the stomach and the risk of atrophic gastritis and intestinal metaplasia is still not well understood. Towards obtaining a better understanding, concentrations of bile acids were measured.

PATIENTS AND METHODS

This study was carried out with the participation of 14 facilities in Japan, and 2283 samples were collected. The subjects with bile acid concentrations equal to or higher than the limit of detection were divided into four groups of equal size (group A: 0-25%, group B: 26-50%, group C: 51-75%, and group D: 76-100%). Thus, including the control group, there were five groups in total. The odds that the control group would develop atrophic gastritis and intestinal metaplasia was set as 1,and the odds ratios (OR) in groups A, B, C and D were calculated based on the odds in the control group.

RESULTS

Regarding the development of atrophic gastritis, no increased risk was observed in either the Helicobacter pylori (H. pylori)-positive or -negative cases. The OR for the development of intestinal metaplasia were significantly higher, for both cases with and without H. pylori infection, in group D.

CONCLUSION

High concentrations of bile acid seem to be associated with an elevated risk of intestinal metaplasia.

Outcome of endoscopic submucosal dissection for gastric neoplasm in relationship to endoscopic classification of submucosal fibrosis

BACKGROUND

Whether submucosal fibrosis is related to ulceration and affects the outcome of endoscopic submucosal dissection (ESD) for early gastric cancer (EGC) is unknown. This study aimed to determine ESD outcome in relationship to degree of submucosal fibrosis of gastric epithelial neoplasms and to identify factors predictive of submucosal fibrosis.

METHODS

Eight hundred ninety-one patients with 1,027 gastric epithelial neoplasms were treated by ESD from April 2005 to January 2011. Complete en bloc resection and perforation rates in relationship to degree of submucosal fibrosis (F0, no fibrosis; F1; mild fibrosis; F2, severe fibrosis) were determined during ESD, as well as degree of concordance between endoscopically observed ulceration and pathologically determined ulceration and pathological fibrosis stained with Masson's trichrome.

RESULTS

The complete en bloc resection rate was significantly low and the perforation rate was high for F2 versus F0/F1 tumors. Ulceration, tumor size ≥30 mm, and depressed histological type were independent risk factors for severe (F2) fibrosis. No fibrosis (F0) was observed in 77% (732/951) of endoscopically negative ulceration cases, whereas fibrosis was observed in 100% (76/76) of endoscopically positive cases. Masson trichrome staining was weak in 97% (710/732) of F0, moderate in 85% (181/214) of F1, and strong in 100% (81/81) of F2 cases.

CONCLUSIONS

Histopathological type of submucosal fibrosis predicts outcome of ESD for EGC. Endoscopic indications of F2 submucosal fibrosis are ulceration, tumor ≥30 mm, and macroscopic depression.

Gastric atrophy, diagnosing and staging

H pylori is now accepted as the cause of gastritis and gastritis-associated diseases, such as duodenal ulcer, gastric ulcer, gastric carcinoma, and gastric MALT lymphoma. The natural history of H pylori gastritis includes inflammation progressing from the antrum into the adjacent corpus resulting in an atrophic front of advancing injury leading to a reduction in acid secretion and eventual loss of parietal cells and development of atrophy. Sub-typing intestinal metaplasia has no clinical value to the patient, the pathologist, or the endoscopist. The pattern, extent, and severity of atrophy, with or without intestinal metaplasia, is a far more important predictor than is intestinal metaplasia subtype. The challenge remains to identify a reliable marker that relates to pre-malignant potential.

Helicobacter pylori eradication in the healing of atrophic gastritis: a one-year prospective study

OBJECTIVE

Whether gastric atrophy or intestinal metaplasia heals after successful treatment of Helicobacter pylori (H. pylori) infection is still a matter of controversy. The aim of this article was to clarify whether, after one year, H. pylori eradication is associated with healing in glandular atrophy and intestinal metaplasia in the corpus and antrum.

MATERIAL AND METHODS

Ninety-two H. pylori-positive peptic ulcer patients with atrophic gastritis (panatrophy, antral or corpus predominant) participated in the baseline study, 1-year prospective follow-up data being available from 76 patients. Mean age was 58+/-12.6 years (mean+/-SD) and the male/female ratio 2/1. The patients participated in an H. pylori eradication study in which they randomly received active eradication therapy. Endoscopy was performed before H. pylori eradication therapy and after 8 and 52 weeks, with specimens examined according to the Sydney system.

RESULTS

Of the 92 patients, 8 (9%) had panatrophy, 58 (63%) had antral- and 26 (28%) had corpus-predominant atrophic gastritis. After H. pylori eradication, the mean atrophy score declined in patients with antral-predominant atrophy from 1.5 (mean) to 0.7 (p<0.05), in corpus-predominant atrophy from 1.7 to 0.2 (p=NS) and in patients with panatrophy from 1.2 to 0.8 (p=NS). Atrophy healing was seen in 55% of antral-predominant atrophy patients who had successful H. pylori eradication. The mean antral atrophic score in one year declined in patients with duodenal ulcer (from 1.0 mean to 0.4) whereas it remained the same (1.3) in those with gastric ulcer (p<0.05).

CONCLUSIONS

Atrophy can diminish or even disappear, especially in the antrum, during a 1-year follow-up after eradication of infection. Atrophy progression seems milder in patients with duodenal ulcer than in patients with gastric ulcer.

General features of gastric carcinomas and comparison of HSP70 and NK cell immunoreactivity with prognostic factors

During the period of 1996-1998 ninety-four gastrectomy specimens with gastric carcinoma referred to Erciyes University, Medical Faculty, Department of Pathology, were examined histopathologically, histochemically and immunohistochemically. General characteristics of gastric carcinomas and prognostic factors were studied. According the Lauren classification, of the 94 cases of gastric carcinomas, 56 were intestinal type, 21 were diffuse type and 17 were mixed type carcinoma. The association rates of Helicobacter pylori, chronic atrophic gastritis and intestinal metaplasia with gastric carcinomas were high. There was strong immunorectivity with HSP70 in 62,5% of the intestinal type carcinomas. This ratios were lower in diffuse and mixed type carcinomas (p<0.05). The more tumor size and invasion depth increased, the more HSP70 immunoreactivity was obtained (p<0.05). HSP70 immunorectivity was considerably higher in the patients having lymph node metastasis and vascular invasion (p<0.05). It was found that the NK cell number was low in the tumor but higher around the tumor in early gastric carcinomas, compared with advanced carcinomas (p>0.05). In the tumors larger than 10 cm with vascular invasion, NK cell number was lower around the tumor (p>0.05). Defining prognostic factors of gastric carcinomas is of importance to clinicians. It is thought that HSP70 immunoreactivity, besides invasion depth, lymph node metastasis, vascular invasion, tumor size and inflammatory reaction against the tumor, is important in prognosis and associated with advanced stage.

Atrophy-metaplasia-dysplasia-carcinoma sequence in the stomach: a reality or merely an hypothesis?

The results of recent investigations have suggested that the old hypothesis of an atrophy-metaplasia-dysplasia-carcinoma sequence in the stomach needs to be qualified. The most common cause of intestinal metaplasia is Helicobacter pylori gastritis. The consequence of this intestinal metaplasia is focal atrophy. Helicobacter pylori infection may also trigger an autoimmune gastritis of the corpus mucosa, with atrophy and intestinal metaplasia. Most intestinal metaplasias are only 'paracancerous' but not 'precancerous' lesions. Diffuse gastric carcinomas, such as the signet ring cell carcinoma, arise independently of intestinal metaplasia. Histogenetically, numerous carcinomas of the stomach are primarily of the gastric type, and may secondarily change into the intestinal type.High-grade intra-epithelial neoplasias (dysplasias) detected during the biopsy-based diagnostic work-up appear to be a marker for carcinoma and must, therefore, be removed endoscopically. The detection of intestinal metaplasia in routinely obtained biopsy material is subject to sampling error and is, therefore, not a suitable marker for an increased risk of a gastric carcinoma developing. As an alternative, the concept of gastritis of the carcinoma phenotype, which is more frequently found in early gastric carcinomas and in the relatives of gastric carcinoma patients, has been developed. In this concept, the diffuse parameters of grade and activity of the gastritis in the antrum and corpus, which are independent of sampling error, are subjected to a comparative analysis. A risk gastritis of the carcinoma phenotype is diagnosed when the grade and activity of the gastritis in the corpus are at least equally as pronounced as in the antrum. Currently, this concept is being tested in a prospective ongoing study. Future studies must show whether, and if so which, immunohistochemical or molecular-genetically detectable changes can be applied as risk markers in the diagnostic work-up. Helicobacter pylori eradication probably does not lead to complete regression of the intestinal metaplasia and ensuing focal atrophy. However, eradication of H. pylori does lead to the normalization of changes that can lead to mutations of the stem cells of the gastric mucosa (free radicals, nitric oxide, cell proliferation and vitamin C secretion).

Gastric intestinal metaplasia: subtypes and natural history

BACKGROUND

It has been suggested that the subtyping of intestinal metaplasia in the stomach is useful in stratifying patients with regard to risk of developing gastric cancer.

AIM

To determine whether subtyping intestinal metaplasia provided useful information regarding the natural history of intestinal metaplasia.

METHODS

The study used large cup gastric biopsy specimens from predetermined locations (gastric mapping). Follow up biopsies were obtained at one, two, and/or nine years. Biopsies with intestinal metaplasia were stained with high iron diamine/Alcian blue (HID/AB) to determine whether they expressed neutral mucins, sialomucins, or sulphomucins.

RESULTS

Seventy nine patients with intestinal metaplasia were studied and characterised with regard to the most advanced subtype of intestinal metaplasia. The most severe type of intestinal metaplasia was type II in 33 patients and type III in 34 patients. Helicobacter pylori was cured in 67 patients. Follow up showed that changes in type of metaplasia (apparent regression or progression) occurred in both directions and were independent of H pylori status. For example, biopsy sites with "loss" of metaplasia at a follow up visit might have it "reappear" at a subsequent visit. During follow up, no patient developed gastric dysplasia or died from gastric cancer.

CONCLUSION

HID subtyping did not provide useful information to the clinician or the pathologist. The data are consistent with the notion that the pattern, extent, and severity of atrophy with/without intestinal metaplasia is a far more important predictor of increased cancer risk than intestinal metaplasia subtype.

Duodenogastric reflux is associated with antral metaplastic gastritis

BACKGROUND

It has long been suspected that duodenogastric reflux plays a role in the pathogenesis of intestinal metaplasia (IM), although recent studies have demonstrated a close association between Helicobacter pylori infection and gastroduodenal diseases, including IM. The objective of this study was to investigate the relation among IM and duodenogastric reflux, H pylori infection, and smoking.

METHODS

Subjects with "marked" characteristics of IM, all with extensive prepyloric distribution at endoscopy that was confirmed histologically, were studied as an IM group (27 men, 26 women; mean age, 64 years). A control group was comprised by subjects without characteristics of IM (29 men, 28 women; mean age, 63 years). Fasting pH, total bile acid concentration, and ammonia concentration were measured in the gastric juice of all participants. Histologic examination endoscopic biopsy specimens were evaluated histologically. H pylori infection was determined by serum antibody and urease testing, and by histology. Serum gastrin and pepsinogen concentrations, and gastric emptying time were measured. Dietary, drinking, and smoking habits were recorded. Comparisons were made between groups and analyzed statistically.

RESULTS

The pH and total bile acid concentrations were significantly higher in the IM group than the control group (p < 0.01). No significant difference in H pylori infection was found between the IM and control group. Smoking was associated with IM (odds ratio [OR], 15.74; 95% CI, 3.96 to 62.50).

CONCLUSIONS

A high pH and total bile acid concentration and smoking were associated with "marked" IM, suggesting that these factors may play a role in the development of IM.

Dual roles of peptic ulcer in the carcinogenesis or extension of early gastric cancer

BACKGROUND

Early gastric cancer (EGC) often coexists with peptic ulcer. In this study we investigated the roles of peptic ulcer in the carcinogenesis and extension of gastric cancer.

METHODS

The clinicopathological characteristics of EGC and peptic ulcer and their relationship, as well as that of the background intestinal metaplasia, were compared among the following three groups: patients with peptic ulcer only inside the EGC (Contained group, 53 patients); patients with peptic ulcer only outside the EGC (Separate group, 26 patients); and patients of EGC with no peptic ulcer (Absent group, 43 patients).

RESULTS

In the Separate group, a male preponderance was observed (P = .006), and all EGCs developed in the middle or lower third of the stomach (P = .06). Most of the EGCs were an intestinal type of cancer with severe background intestinal metaplasia. Topographically, 88% of the peptic ulcers in the Separate group developed proximal to the EGC. On the other hand, in the Contained group, most EGCs developed in the middle third of the stomach with an intestinal/diffuse type ratio of 1:1. Peptic ulcers inside the EGC were significantly more shallow than those that developed outside the EGC (P = 0.008). Although the incidences of submucosal cancer were nearly the same among the three groups, the maximum cancer diameter tended to be increased in the Contained group compared to that in the Absent group, and the incidence of lymph node involvement tended to be higher in the Contained group (8%) as compared with the other two groups (4%-5%).

CONCLUSIONS

These results suggest that peptic ulcer outside the EGC contributes to the development of the intestinal type of EGC, with the background of more severe intestinal metaplasia during the peptic ulcer healing processes, whereas peptic ulcer inside the EGC develops secondary to EGC and favors cancer extension and metastasis. Peptic ulcer associated with EGC can be considered to exert different biological roles in the carcinogenesis or extension of ECG according to the location of the peptic ulcer.

Bile reflux and intestinal metaplasia in gastric mucosa

AIM

To determine associations between enterogastric bile reflux and gastric mucosal pathology.

METHOD

A retrospective study using fasting gastric juice bile acid measurements and antral or prestomal biopsy specimens from 350 patients, 66 of whom had previously undergone surgery that either bypassed or disrupted the pyloric sphincter.

RESULTS

Bile reflux was positively associated with reactive gastritis and negatively with Helicobacter pylori density. After stratification for previous surgery, age, and H pylori status, the histological feature most strongly associated with bile reflux was intestinal metaplasia, including all its subtypes. The prevalence of intestinal metaplasia was greatest in patients with both H pylori infection and high bile acid concentrations. Bile reflux was also positively associated with the severity of glandular atrophy, chronic inflammation, lamina propria oedema and foveolar hyperplasia.

CONCLUSIONS

Bile reflux is a cause of reactive gastritis. It modifies the features of H pylori associated chronic gastritis. The changes are not confined to patients who have had surgery to their stomachs. The positive associations with atrophy and intestinal metaplasia have implications for models of gastric carcinogenesis.

Gastric intestinal metaplasia type III cases are classified as low-grade dysplasia on the basis of morphometry

The aim of this study was to try to place gastric intestinal metaplasia, type III (type III IM) in the stepwise chain of events from atrophic gastritis to cancer. A number of dysplastic, periulcer regenerative, and type III IM lesions were qualitatively diagnosed (and graded) blindly and independently by several pathologists. These lesions were further analysed by means of quantitative parameters, with the aim of differentiating dysplastic from regenerative changes. Inconsistencies between the qualitative and quantitative classification (about 7 per cent of cases) were eliminated and homogeneous groups (low-grade dysplasia, high-grade dysplasia, regenerative changes) were obtained. These cases were taken as the gold standard against which type III IM was compared. The results indicate that the great majority (91.4 per cent) of cases of type III IM fulfil the nuclear and architectural criteria for low-grade dysplasia.

Changes in gastric mucosa that antedate gastric carcinoma

Endoscopic biopsy specimens of the gastric mucosa from 13 patients who were found at follow-up examination to have gastric carcinoma were compared for abnormal histologic features, type of intestinal metaplasia, and presence of immunoreactive carcinoembryonic antigen (CEA), with specimens from 40 tumor-free controls. Villus-like changes and angular infolding, cytologic nuclear pleomorphism, distinct nuclear border, irregular thickness of the nuclear membrane, irregular chromatin clumping, prominent nucleoli, and distinct nucleoli were manifestations of the carcinoma group. Angular infolding, distinct nuclear border, irregular thickness of the nuclear membrane, and distinct nucleoli were also observed in the latent stage before detection of carcinoma. The individual features, however, lacked specificity. Histochemically, a IIB subtype of intestinal metaplasia, and immunoreactive CEA in the cytoplasm of foveolar epithelium appeared exclusively in the patients with carcinoma. These findings indicate that the gastric epithelium of patients with gastric carcinoma tends to be morphologically and histochemically abnormal even before the recognition of classical dysplasia. This can be described as abnormal epithelium and is believed to provide the soil on which gastric carcinoma develops.

Morphometric distinction of low- and high-grade dysplasias in gastric biopsies

Substantial agreement has previously been demonstrated between qualitative and morphometric grading of gastric dysplasia. In the present study, a further attempt is made to quantitatively define the dysplastic changes in relation to associated benign or malignant changes of gastric mucosa. In total, 232 cases were studied and were associated with benign peptic ulcer (89 cases), histologically proven gastric cancer (88 cases), and gastritis-associated mild, moderate, and severe dysplasias (55 cases). The analysis showed that one discriminant function consisting of seven morphometric features is sufficient to separate the regenerative and cancer-associated cases. The classification results obtained on the basis of this discriminant function in both training and testing sets are encouragingly similar, indicating that the classification is reliable. This was further confirmed by the results of the application of this rule in the mild, moderate, and severe dysplasia biopsies (the above-mentioned gastritis-associated cases) used in a previous study. The quantitative analysis permits two grades, instead of three, to be distinguished: low-grade and high-grade dysplasia.

Short-term effects of bile diversion on postgastrectomy gastric histology

Twelve partially gastrectomized subjects who have consecutively undergone total biliary diversion for severe bilious vomiting were studied before and after operation in order to assess the effects of surgery on gastric histology and enterogastric reflux. Before and six months after operation, the following protocol was performed: (1) blood examinations including serum basal gastrin; (2) endoscopy with multiple gastric biopsies; and (3) quantitation of bile acids in the gastric aspirate. Of the preoperative symptoms, bilious vomiting and heartburn completely disappeared postoperatively in all the subjects. Fasting bile reflux was significantly reduced (bile reflux was annulled in six and considerably lowered in the remaining six subjects), and erythema of the gastric mucosa completely disappeared in all the subjects after diversion. Among histological findings, while a significant regression of foveolar hyperplasia was found both in the perianastomotic area and in the body of gastric remnant, none of the other aspects identifiable in postgastrectomy gastric mucosa (chronic gastritis changes included) were affected by diversion. These results show that biliary diversion is effective in correcting reflux, bilious vomiting, erythema, and foveolar hyperplasia of the gastric mucosa and confirm the suggested relationship between bile reflux and gastric foveolar hyperplasia.

Gastric histology and fasting bile reflux after partial gastrectomy

Forty-four randomized, partially gastrectomized subjects were studied to assess whether gastric histologic findings after partial gastrectomy were related to reflux. Gastric biopsy specimens (12) were taken at different distances from the anastomosis. Histologic findings were as follows: (a) hyperplastic changes of the foveolar epithelium and (b) loss of the chief and parietal gland cells with atrophy of gastric glands (chronic atrophic gastritis). Hyperplastic changes typical of the perianastomotic area gradually decreased with increasing distance from the anastomosis. Hyperplastic changes showed a greater prevalence in Billroth II than in Billroth I subjects (100% vs. 29.4%). No significant association was found between histologic findings and symptoms. Hourly bile acid quantity (fasting bile reflux) and concentration were determined in the gastric aspirates. Bile reflux was greater after Billroth II than after Billroth I (fasting bile reflux median values: 30.5 vs. 0.18 mumol/h, respectively). The same was true for bile acid concentration (mean bile acid concentration median values: 624.9 vs. 17.5 mumol/L, respectively). Moreover, Billroth I subjects with hyperplasia had a greater quantity and concentration of reflux than those without hyperplasia (fasting bile reflux and mean bile acid concentration median values: 2.6 vs. 0.8 mumol/h and 4.7 vs. 2.7 mumol/L, respectively). These findings show that bile reflux is correlated with hyperplastic changes of the foveolar epithelium, but prevalence and severity of atrophic gastritis were not related to reflux. Therefore, although we failed to show any relationship between chronic atrophic gastritis and reflux, foveolar hyperplasia was shown to be reflux related.

Histopathogenesis of intestinal metaplasia: minute lesions of intestinal metaplasia in ulcerated stomachs

Minute lesions of intestinal metaplasia composed of a few metaplastic tubules were observed in the gastric mucosa during routine histological examination of gastrectomy specimens. The histological findings indicated that these lesions might be an initial stage of more advanced intestinal metaplasia. Accordingly, more than 18,000 serial sections in 10 stomachs with chronic ulcers were examined to clarify the histopathogenesis of the intestinal metaplasia. It was concluded from the three dimensional reconstruction of minute intestinal metaplasia lesions that these lesions originated during the regenerative process of healing of gastric erosions. The lesions were roughly globoid with a depression on the surface. It is thought that with continuous formation and healing of gastric erosions, more extensive intestinal metaplasia lesions would be formed by an increase in size and confluence of these focal minute intestinal metaplasia lesions.