Mauro Cassaro

Topographic patterns of intestinal metaplasia and gastric cancer

OBJECTIVE:The role of intestinal metaplasia in gastric oncogenesis has been demonstrated by both cross-sectional and longitudinal studies. This study was designed to determine whether, in a population at high risk for gastric cancer, different topographical patterns and phenotypes of intestinal metaplasia were associated with different degrees of cancer risk.METHODS:A total of 68 Colombian patients with gastric cancer and 67 controls with nonulcer dyspepsia were studied by an extensive biopsy protocol. Intestinal metaplasia was assessed semiquantitatively by histology and was characterized histochemically. In both patients and controls, the Spearmans correlation test was applied to the test if the gastric distribution of metaplastic lesions resulted in specific topographical patterns associated with different risks for cancer.RESULTS:Four topographical patterns of intestinalization emerged: 1) “Focal,” in 14 cancer patients and 16 controls; 2) “Antrum-predominant,” in seven cancer patients and six controls; 3) “Magenstraße” (involving the lesser curvature from cardia to pylorus) in 25 cancer patients and four controls. This pattern was associated with higher cancer risk (OR = 5.7; 95% CI: 1.3–26) than were the two less extensive patterns; and 4) “Diffuse,” involving essentially the entire gastric mucosa with the exception of the fundus, was unique to 13 cancer patients. The OR for cancer was 12.2; 95% CI: 2.0–72.9. Incomplete-type metaplasia significantly correlated with the extent of total metaplasia and was also associated with greater cancer risk.CONCLUSIONS:In a population with high risk for gastric cancer, the extension of intestinal metaplasia correlates with the extent of its “incomplete” phenotype and is significantly associated with increased cancer risk. Both the extent and location of intestinal metaplasia along the lesser curvature (from the cardia to the prepyloric zones) identify patients with the highest cancer risk.

The long term outcome of gastric non-invasive neoplasia

Background: The cancer risk associated with gastric non-invasive neoplasia (formerly dysplasia) is debated. This prospective long term follow up study investigates the clinicopathological behaviour of non-invasive gastric neoplasia (and related lesions), focusing on the cancer risk associated with each different histological phenotype. Patients and methods: A total of 118 consecutive cases (nine indefinite for non- invasive neoplasia; 90 low grade non-invasive neoplasia; 16 high grade non- invasive neoplasia; and three suspicious for invasive adenocarcinoma) with a histological follow up of more than 12 months (average 52 months; range 12–206) were prospectively followed up with a standardised protocol. Patients in whom gastric cancer was detected within 12 months from the initial diagnosis of non-invasive neoplasia were excluded, assuming that invasive carcinoma had been missed at the initial endoscopy procedure. Results: Non-invasive neoplasia was no longer detectable in 57/118 cases (48%), was unchanged in 32 (30%), and evolved into gastric cancer in 20 patients (17%). Evolution to invasive adenocarcinoma was documented in both low and high grade non-invasive neoplastic lesions (8/90 low grade; 11/16 high grade) and correlated with histological severity (low versus high grade) at baseline (p<0.001). Seventy five per cent of cancers occurring during the long term follow up were stage I. Conclusions: The risk of invasive gastric cancer increases with the histological grade of the non-invasive neoplasia. Following up non-invasive gastric neoplasia increases the likelihood of gastric cancer being detected in its early stages.

Patients younger than 40 years with gastric carcinoma

In the general population, Helicobacter pylori (H. pylori), particularly the cagA positive strain, has been associated with intestinal‐type gastric carcinoma. Gastric carcinomas are rarely observed in patients age ≤40 years. Host‐related factors have been thought to be more important than environmental agents in these early‐onset cancers. The aim of this study was to ascertain the possible role of H. pylori infection and that of cagA positive strains in the development of gastric carcinoma in these young patients.

Gastric epithelial dysplasia. How clinicopathologic background relates to management

Background. Gastric epithelial dysplasia (GED) in metaplastic mucosa is considered the most advanced preinvasive lesion in the multistep morphogenesis of intestinal‐type gastric cancer (GC). The rate of GEDs evolution into GC is still under debate and probably is related to pathologic and clinical parameters other than the dysplasia itself. The aim of this study was to evaluate whether clinical aspects (sex and age) and/or morphologic variables (GED grade, coexisting atrophic gastritis) are relevant to the outcome of dysplasia, with a view toward initiating the establishment of a rational follow‐up protocol for practical GED management.

Helicobacter pylori in promotion of gastric carcinogenesis

Gastric atrophy and intestinal metaplasia are considered the earliest phenotypic changes in the cascade of events leading from normal mucosa to intestinal-type gastric cancer, and epidemiological evidence linksHelicobacter pylori to gastric epithelial malignancies. To evaluate any causal relationship between bacterial infection and atrophic metaplastic lesions, gastric pathology was histologically and histochemically evaluated in 267 consecutive, nonulcerous, untreated subjects, with attention given to the phenotypes of intestinal metaplasia. The prevalence ofHelicobacter pylori infection was 61%. Intestinal metaplasia (particularly types II and III) was significantly associated with bothHelicobacter pylori detection (xLR2:P<0.002) and increasing age (xLR2:P<0.002). Using logistic regression analysis, the development of intestinal metaplasia proved more significantly linked withHelicobacter pylori infection [odds ratio=4.55 (95% confidence interval: 1.51–13.7)], than with age [odds ratio =1.03 (95% CI: 1.01–1.06)], with no interaction. In conclusion,Helicobacter pylori can be considered among the major causal agents of mucosal lesions involved in the multistep process of gastric carcinogenesis, justifying any attempt to eradicate this bacterial infection.

Liver stellate cells in chronic viral hepatitis: the effect of interferon therapy

BACKGROUND/AIMS Liver stellate cell proliferation and differentiation into myofibroblast-like cells is related to the development of liver fibrosis. Several cytokines, including interferons, regulate liver stellate cell proliferation and phenotypic modulation. Recent studies indicate that human liver stellate cells express the alpha-isotype of actin, specific to smooth muscle cell differentiation. We aimed to evaluate the expression of alpha-smooth muscle actin-positive liver stellate cells in patients with chronic viral hepatitis and to evaluate whether and how such expression can be modified by alpha-interferon treatment. METHODS Using immunohistochemistry, and a semi-quantitative scoring method, we evaluated alpha-smooth muscle actin expression in liver stellate cells before and after alpha-interferon therapy in a series of liver biopsies from 44 patients with chronic viral hepatitis. RESULTS Before therapy, a large number of liver stellate cells expressing alpha-smooth muscle actin were present throughout all acinar zones. A significant reduction in alpha-smooth muscle actin expression by liver stellate cells was demonstrated in biopsies performed after suspending the interferon treatment. The drop in the number of alpha-smooth muscle actin-labelled cells after therapy correlated closely with the improvement in the histological index of activity. CONCLUSIONS The results suggest a specific effect of interferon on liver stellate cells, possibly related to its anti-inflammatory action.

Helicobacter pylori, inflammation, oxidative damage and gastric cancer : a morphological, biological and molecular pathway

Gastric carcinogenesis is a complex, multistep and multifactorial event, characterized by progressive cyto-histological dedifferentiation, in which the role of Helicobacter pylori infection has been established. Among the pathways relevant to gastric carcinogenesis and correlated with H. pylori infection, it has been demonstrated that the production of reactive oxygen species, with damage to the DNA, may be quite important. Oxidative damage, alone and/or in combination with exogenous and endogenous factors, induces several molecular changes. The assumption is that, in precancerous lesions, these molecular changes belong to the same biological spectrum as their invasive counterpart. The molecular profile of these preneoplastic lesions is heterogeneous, however, and there are still no molecular markers enabling the distinction between atypical hyperplastic lesions and low-grade noninvasive neoplasia (NiN) or between high-grade NiN and early invasive neoplasia. Indeed, within the spectrum of morphological changes characterizing this multistep evolution, dysplasia (NiN) is the lesion coming closest to the development of invasive adenocarcinoma. Several of the genetic and epigenetic alterations reported in gastric precancerous lesions affect DNA repair system genes, tumor suppressor genes, oncogenes, cell cycle regulators, growth factors, and adhesion molecules. Although we await reliable molecular markers, it is best to monitor patients harboring NiN closely with endoscopy and extensive bioptic sampling, and to eradicate any H. pylori to prevent the accumulation of oxidative DNA damage and its consequent progression. The growing body of evidence of the regression of precancerous changes and the high prevalence of superficial gastric carcinoma demonstrated in long-term follow-up studies on NiN make this approach mandatory.

Oxidative DNA damage in gastric cancer : cagA status and OGG1 gene polymorphism

Oxidative DNA damage is thought to play an important part in the pathogenesis of H. pylori‐induced mucosal damage. 8‐OHdG is a sensitive marker of DNA oxidation and is repaired by a polymorphic glycosylase (OGG1) more effectively than by OGG1‐Cys326. The aims of this study were to ascertain the respective roles of H. pylori, cagA status and OGG1 polymorphism in determining 8‐OHdG levels in benign and premalignant stomach diseases and in gastric cancer (GC). The study involved 50 GC patients (for whom both neoplastic tissue and surrounding mucosa were available), 35 with intestinal metaplasia and atrophy (IMA) and 43 controls. H. pylori and cagA status were determined by histology and polymerase chain reaction for urease and cagA. 8‐OHdG was assayed using HPLC with an electrochemical detector (HPLC‐ED). The OGG1 1245C→G transversion was identified using RFLP analyses. 8‐OHdG levels were significantly higher in GC, with no differences in relation to H. pylori or cagA status. OGG1 polymorphism was documented in 34% of GC (15 Ser/Cys, 2 Cys/Cys). OGG1 1245C→G polymorphism was detected in 54% of IMA patients, but only 16% of controls (p = 0.0004) and coincided with significantly higher 8‐OHdG levels. In the multivariate analysis, 8‐OHdG levels were predicted by histotype and OGG1 status. OGG1 1245C→G polymorphism was common in both GC and IMA, but very rare in controls, and correlated more closely with 8‐OHdG levels than do H. pylori infection or cagA status.

Pathology of the gastric antrum and body associated with Helicobacter pylori infection in non-ulcerous patients: is the bacterium a promoter of intestinal metaplasia?

A series of 115 consecutive, non‐ulcerous, dyspeptic patients were examined for Helicobacter pylori (H. pylori) colonization in the gastric antral and/or body mucosa using Giemsa staining. Findings were correlated with the presence and degree of activity of superficial gastritis, deep gastritis, atrophic gastritis and with the presence of intestinal metaplasia. The prevalence of H. pylori positivity was 61.7%. In 59 of the 71 positive patients (83%), H. pylori was detected in the antrum or in both the antral and oxyntic mucosa. In the remaining 12 positive patients, H. pylori was detected only in the oxyntic mucosa and in all these cases, the antrum showed intestinal metaplasia associated with atrophic gastritis (25%). In both antral and oxyntic mucosa, the activity of the gastritis was significantly correlated with H. pylori colonization. Linear logistic regression analysis showed that in patients with intestinal metaplasia the presence of H. pylori infection was significant in predicting the presence of more extensive intestinal metaplasia after adjusting for age. The prevalence of intestinal metaplasia types II and III was 65.5% in the H. pylori positive and 25% in the H. pylori negative patients. The antral mucosa is thought to be the elective site for H. pylori related histological lesions. At a later stage, H. pylori can be detected only in the oxyntic area while the antral mucosa shows extensive metaplastic or atrophic lesions. We would suggest that H. pylori plays a promotional role in the morphogenesis of intestinal metaplasia.

Barrett's epithelium after antireflux surgery.

Barrett’s epithelium (BE), defined as endoscopically visible, histologically proved intestinal-type epithelium in the esophagus, is considered the ultimate consequence of long-standing gastro(duodeno)esophageal reflux disease (GERD). Recent reports suggest that effective antireflux therapy may promote the regression of this metaplastic process. This study aimed to establish whether antireflux surgery (laparoscopic fundoplication) can induce any endoscopic and/or histologic changes in BE. Thirty-five consecutive cases of BE (11 short-segment [SBE] and 24 long-segment [LBE]) were considered. All patients underwent extensive biopsy sampling before and after surgery (mean follow-up, 28 months; range, 12–99 mo). In all cases, (a) intestinal metaplasia (IM) extension (H&E), (b) IM phenotype (high-iron diamine [HID]), and (c) Cdx2 immunohistochemical expression were histologically scored in the biopsy material obtained before and after fundoplication. After surgery, a significant decrease in IM extension and a shift from incomplete- to complete-type IM were documented in SBE. No significant changes occurred in the LBE group in terms of IM extension or histochemical phenotype. A drop in the immunohistochemical expression of Cdx2 protein was also only documented in the SBE group. Antireflux surgery significantly modifies the histologic phenotype of SBE, but not of LBE.