Importance of atrophic gastritis in diagnostics and prevention of gastric cancer: application of plasma biomarkers.
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Publications and source records attributed to Pentti Sipponen.
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Gastric cancer (GCA) displays a variety of genomic aberrations, including DNA copy number alterations, microsatellite instability (MSI), and loss of heterozygosity (LOH). The main aim of the present work was to determine the copy number aberrations in tumors with and without MSI or LOH. Fifteen fresh-frozen GCA samples, 11 of the intestinal and 4 of the diffuse type, were grouped by microsatellite analysis into high-level MSI (MSI-H, n = 2), LOH (n = 5), and microsatellite stable, LOH not detected (MSS/LOH-N, n = 8) tumors. The DNA samples were subsequently analyzed by array comparative genomic hybridization with 16,000 cDNA clones. As expected, the LOH tumors showed more copy number changes; however, the frequency of small-size amplifications was similar across all tumor groups. In addition, the cDNA arrays detected two apparently single-gene amplicons, at 11q13 (CCND1) and 12p12.1 (K-RAS), the presence of which were confirmed using oligonucleotide arrays. A novel amplicon at 5q13.2 was found only in diffuse-type tumors, which were otherwise genetically stable. The results suggest that DNA copy number changes may also occur in gastric cancers that show genomic stability in microsatellite analysis.
Several attempts to classify gastric cancer (GCA) have been made over the past decades. Most successful, and widely used, is the classification by Laurén, which distinguishes, by microscopical morphology alone, two main cancer pathogeneses, diffuse (DGCA) and intestinal (IGCA) subtypes, which appear clearly as dissimilar clinical and epidemiological entities. Here we review the main differences in epidemiology, histopathology, and molecular pathology of the two main subtypes of gastric carcinomas based on Laurén classification. In clinical practice, however, clinical staging, particularly in predicting the survival, still remains superior to all classifications of gastric cancer independent of cancer type. The existence of local precursor lesions or conditions of IGCA tumours, i.e. Helicobacter pylori gastritis, atrophic gastritis (AG), intestinal metaplasia (IM), adenoma, dysplasia, and intramucosal neoplasia, is firmly established. The links of DGCA with intestinal-type epithelium, AG or IM are poor, or do not exist. So far, H. pylori gastritis is the only universal precursor condition for DGCA. It implies that AG and achlorhydria are of minor significance and infrequent in the development of DGCA but are important steps in that of IGCA. Despite an increasing body of data, the overall view on molecular pathology of GCA remains fragmentary. No consistent differences in the molecular pathology of GCA subtypes to meet the Laurén classification have been established. With the exception of TP53, no gene mutation occurring regularly in both histological types of GCA has been reported. Chromosomal aberrations and loss of heterozygosity seem to be non-specific and do not follow any consistent route in the progression of GCA. Microsatellite instability is more commonly found in IGCA than in DGCA. The present epigenetic data suggest that most of the decrease (or loss) of gene expression may be explained by promoter hypermethylation which is more often found in IGCA. In DGCA specific genes such as CDH1 are more often hypermethylated. Compared with GCA, in premalignant condition lesions gene mutations and chromosomal aberrations are infrequent. Epigenetic dysregulation might also represent a major mechanism for altered gene expression in premalignant stages in gastric carcinogenesis.
Genomic instability can be divided into 2 categories: chromosomal instability (CIN) and microsatellite instability (MSI). CIN has been linked to aneuploidy and chromosomal aberrations, and high-level loss of heterozygosity (LOH-H) has been suggested to be an indicator of CIN. High-level MSI (MSI-H), which results from nonfunctional mismatch repair, has previously been suggested to be mutually exclusive with CIN. Four MSI-H and three LOH-H primary gastric tumors of intestinal histology were used for copy number analysis by array-based comparative genomic hybridization (aCGH) with 13,000 cDNA targets. The MSI-H group showed fewer gains (0-12, average 4.5) and losses (0-10, average 2.5) per tumor as compared to the LOH-H group (9-15 gains, average 11.6 and 1-6 losses, average 4). Two MSI-H tumors did not show any copy number changes and one showed only gains of whole chromosomes. The most common alterations were gains of 20q (5/7 samples), 1q, 8, and 10p (3/7 samples) and losses of 1p and 5p (3/7 samples). The minimal amplified regions in 1q and 20q were localized to 1q21.1 approximately q21.2, 1q21.3, 20q11.2, 20q13.12, and 20q13.3 approximately qter. No copy number change was found to be specific for MSI-H or LOH-H. The results suggest that the LOH-H phenotype revealed by microsatellite analysis predicts reliably copy number abnormalities on aCGH and that a subset of MSI-H and all LOH-H tumors share the CIN phenotype.
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.
BACKGROUND: All the risk factors of peptic ulcer disease are not thoroughly understood. GOALS: To assess duodenal gastric metaplasia (DGM) in relation to Helicobacter pylori status and endoscopy findings with special reference to the effects of highly selective vagotomy. STUDY: The study population consisted of 1056 adult patients and an additional 154 patients who had had a highly selective vagotomy. Their clinical and endoscopy records as well as the histology of gastric and duodenal biopsies were evaluated retrospectively. H. pylori infection had been determined by serology and culture. RESULTS: Widespread (more than 20%) DGM was strongly associated with H. pylori positive duodenal ulcer disease (in 59.7% of patients). The prevalence of DGM diminished progressively the more proximally the ulcer was located in the stomach, and was 2.5% in proximal gastric ulcers patients. In vagotomized patients, the prevalence of widespread DGM (8.4% of patients, median 14 years after operation and the majority still H. pylori positive) was close to that of patients with H. pylori gastritis without peptic ulcer disease (4.5%). CONCLUSIONS: Widespread DGM is an indicator for an increased risk of duodenal ulcer among H. pylori positive patients and it could be used to select patients for eradication therapy.
Even though Helicobacter pylori infection is an obvious cause of chronic non-atrophic and atrophic gastritis, as well as gastric dysplasia and cancer, several recent controlled intervention trials for the prevention of gastric cancer by H. pylori eradication have yielded disappointing results. They showed that cancer eradication may still appear in relatively high frequency after successful treatment of H. pylori. One explanation for this observation is that H. pylori treatment has less influence in development of gastric cancer in atrophic gastritis than in development of cancers in non-atrophic gastritis, and that eradication does not prevent the progression of precancerous lesions and small invisible early cancers to overt tumors. Noteworthy however, the available intervention trials show that gastric cancer can be prevented by H. pylori treatment in patients with non-atrophic gastritis. Trials with higher number of patients, with longer follow-up periods, and with more careful controlling of cancer type and underlying gastric mucosal conditions are needed.
AIM: To examine whether the fasting levels of serum gastrin-17 (G-17) are lower in Barrett's esophagus (BE) patients than in non-Barrett controls. METHODS: Nineteen patients with BE (presenting with a tubular segment > or =2 cm long in lower esophagus and intestinal metaplasia of incomplete type ("pecialized columnar epithelium") in endoscopic biopsies from the tubular segment below the squamocolumnar junction were collected prospectively from outpatients referred to diagnostic gastroscopy. The controls comprised 199 prospectively collected dyspeptic outpatients without BE or any endoscopically visible lesions in the upper GI tract. Fasting levels of serum G-17 (G-17fast) were assayed with an EIA test using a mAb highly specific to amidated G-17. None of the patients and controls received therapy with PPIs or other antisecretory agents. RESULTS: The mean and median levels of G-17fast in serum were significantly lower (P = 0.001) in BE patients than in controls. The positive likelihood ratios (LR+) of low G-17fast to predict BE in the whole study population at G-17fast levels <0.5, <1, or <1.5 pmol/L were 3.5, 3.0, and 2.8, respectively. Among patients and controls with healthy stomach mucosa, the LR+ were 5.6, 3.8, and 2.6, respectively. In the whole study population, serum G-17 was below 2 pmol/L in 15 of 19 BE patients (79%). The corresponding prevalence was 66 of 199 (33%) in controls (P<0.001). The G-17fast was 5 pmol/L or more in only one of the 19 BE patients (5%). In controls, 76 of the 199 patients (38%) had such high serum G-17fast levels (P<0.01). CONCLUSION: Serum levels of G-17fast tend to be lower in native patients with BE than in healthy controls.
BACKGROUND: Microsatellite instability (MSI) and loss of heterozygosity (LOH) are lesions in the genome found with different frequencies in gastric carcinomas (GCAs). Despite a great body of studies, no systematic approach to the detailed classification of MSI and LOH in the two major types of GCA has been published. METHODS: Thirty-seven advanced GCAs, 25 intestinal-type (IGCAs) and 12 diffuse-type (DGCAs), were assayed with 15 autosomal tetranucleotide markers on 14 chromosomal arms. The observed frequencies and types of microsatellite alterations allowed stratification into subgroups, i.e., high- and low-grade MSI (MSI-H, MSI-L) or microsatellite-stable (MSS), and high- or low-grade, or non-detectable LOH (LOH-H, LOH-L, LOH-N). RESULTS: Collectively, the markers detected MSI-H tumors with sensitivity equal to that of BAT-26 (a single marker highly specific for MSI-H). Likewise, the markers detected LOH at chromosomal arms 5q, 18q, and 21q with a sensitivity equal to markers used previously. Seven (19%) MSI-H and six (16%) LOH-H tumors were found, with a significant association (P = 0.027) with IGCA: 92% of MSI-H and LOH-H occurred in IGCA patients only. Conversely, in DGCA, a significantly higher prevalence of a stable (LOH-N/MSS) phenotype was found as compared with IGCA (75.1% vs 28.0%; P = 0.035). The MSI-L phenotype was found in 57.9% of non-MSI-H IGCA tumors and was associated significantly (P = 0.015) with LOH-H. CONCLUSION: A clear difference in genomic instability between IGCA and DGCA was found. In IGCA, the MSI and LOH pathways were more commonly involved, whereas in DGCA, a stable phenotype was predominant. As a novel finding, MSI-L as a true phenomenon and its association with LOH was observed in IGCA.
OBJECTIVE: Reliable and readily available non-invasive methods are needed for detection of Helicobacter pylori infection and assessment of eradication therapy. In H. pylori-positive subjects we compared three stool antigen tests (Premier Platinum HpSA, Amplified IDEIA HpStAR and ImmunoCard STAT!HpSA) with invasive tests before their eradication therapy, and with non-invasive diagnostic methods after their therapy. MATERIAL AND METHODS: A total of 82 adults with dyspepsia (aged 24-79 years) with an H. pylori-positive rapid urease test were enrolled in the study. Before therapy, H. pylori status was also confirmed with histology, culture and serology. After eradication, success was assessed with the [13C]-urea breath test (UBT) and usually also with serology. RESULTS: At baseline, sensitivities of these stool antigen tests were 90.2% for HpSA, 97.6% for HpStAR and 96.3% for ImmunoCard. Eradication therapy was successful in 66 patients and unsuccessful in 16. Sensitivity and specificity of the three stool antigen tests in the post-eradication setting were, respectively, 75.0% and 95.5% for HpSA, 93.8% and 98.5% for HpStAR and 87.5% and 95.5% for Immunocard. CONCLUSIONS: The performance of all three stool antigen tests in the post-treatment setting was slightly inferior to that of the UBT test and serology, with monoclonal antibody-based tests showing better results.
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OBJECTIVES: It is uncertain whether eradication of Helicobacter pylori--without a prolonged suppression of acid secretion--is sufficient to allow healing of peptic ulcers. We evaluated whether eradication of H. pylori with no following anti-secretory medication then administered is sufficient for treatment of peptic ulcers. We also looked at the impact of non-steroidal anti-inflammatory drug (NSAID) and acetylsalicylic acid (ASA) use on ulcer relapses. METHODS: The effect of eradication on ulcer healing and relapse rate was analysed in 115 patients, randomly allocated to four treatment groups: (1) quadruple therapy (28); (2) dual therapy (n-30); (3) triple therapy (n=27); and (4) lansoprazole and placebo (n=30). Endoscopic assessment was performed at 0, 8, and 52 weeks. RESULTS: The ulcer healing rate was 100% [95% confidence interval (CI), 95-100%] in H. pylori-negative and 83% (95% CI, 67-94%) in H. pylori-positive patients (P<0.01). In patients who used NSAIDS or ASA, the healing rates was 100% (95% CI, 73-100%) and 75% (95% CI, 19-99%) in H. pylori-negative (12 patients) and H. pylori-positive patients (four patients) (P = not significant). Ulcer relapses occurred in 5% (95% CI, 1-13%) of H. pylori-negative and in 36% (95% CI, 19-56%) of H. pylori-positive patients (P < 0.01). In H. pylori-negative patients who used NSAIDs or ASA the ulcer relapse rate was 30% (95% CI, 7-65%), whereas the ulcer relapse rate was 2% (95% CI, 0.4-10%) in patients who did not use NSAIDs or ASA (P < 0.05). No difference in ulcer relapse rate in H. pylori-positive patients who used or did not use NSAIDs or ASA was found. The eradication rate of H. pylori was 93% (95% CI, 76-99%) in the quadruple therapy group, 83% (95% CI, 64-94%) in the dual therapy group, 100% (95% CI, 87-100%) in the triple therapy group, and 0% (95% CI, 0-12%) in the lansoprazole and placebo group. CONCLUSIONS: Eradication treatment for H. pylori-positive gastric or duodenal ulcer is sufficient, with no need to follow it with anti-secretory medication. Cure of the infection reduces ulcer relapses in patients who did not use NSAIDs or ASA.
Helicobacter pylori infection continues to play a key role in gastric diseases. Colonization of the gastric mucosa with the bacterium invariably results in the development of chronic gastritis and subsets of patients have a progression of the chronic gastritis to either ulcer or cancer. Epidemiological evidence indicates that the proportion of all gastric cancers attributable to H. pylori infection, and hence potentially preventable upon elimination of this risk factor, is somewhere in the range of 60% to 90%. This portends significant benefit in terms of morbidity and mortality, not least in populations with high prevalence of H. pylori infection coupled with high incidence of gastric cancer. The effect of prophylactic H. pylori eradication on gastric cancer incidence in humans remains unknown, however. Results from randomized trials are eagerly awaited, but availability of strong conclusive results may take many years. A growing number of studies show considerable variation in risk for gastric cancer development, depending on H. pylori strain type and the genetic predisposition of the host. There is also a remote possibility that elimination of the infection may have adverse health implications (e.g., antibiotic resistance), and therefore "simple" risk stratification and targeted chemoprevention is required. Based on "in depth" evidence presented at this workshop, the majority of the scientific task force favored a search-and-treat strategy in first-degree relatives of gastric cancer patients and an overwhelming majority felt that a more general screen-and-treat strategy should be focused in the first instance on a population with a high incidence of H. pylori-associated diseases.
DNA profiling of a cancer tissue can be problematic because of genomic instability. Here we have analyzed gastrointestinal cancer specimens from 46 males, of which seven (15%) showed aberrations in determination of gender by the widely used amelogenin test. The X-type amelogenin allele in all cases remained intact. All male tumor samples showing frequent autosomal loss of heterozygosity had a decreased signal of the Y allele from the amelogenin marker. When tested with an alternate set of primers for the amelogenin locus, the Y-type allele showed loss of heterozygosity in the same seven cases. However, when amplified with 15 Y-specific STR primers, all the cancerous tissue Y chromosomes seemed to be intact. These results indicate when malignant neoplastic tissue specimens are used, that amelogenin-based gender determination should be carefully interpreted.
Background. Only a few reported studies focus on the natural history and course of advanced and severe chronic atrophic gastritis. Methods. In this study we followed 47 men (mean age 62 years) with advanced (moderate or severe) Helicobacter pylori-positive atrophic corpus gastritis. Duration of endoscopic follow-up was 6 years and follow-up based on serum levels of pepsinogen I and antibodies to H. pylori covered a period of 10 years. None of the patients was treated for H. pylori infection prior to end of follow-up. Results. The median H. pylori antibody titre declined (IgG from 4000 to 1300; IgA from 200 to 50) in the study population, and 11 men (23%) converted to seronegative (p=0.0005, Fisher's exact test). There was a small but significant (p=0.0004, Page's test) declining trend in mean atrophy score of the corpus during follow-up (from 2.5 to 2.2). However, no significant changes were observed in grade of atrophy or intestinal metaplasia of the antral mucosa or in grade of intestinal metaplasia in the corpus. The mean SPGI level remained at the initial low level during the entire follow-up. Conclusions. H. pylori antibodies disappear spontaneously within 10 years in almost one fourth of patients with advanced atrophic corpus gastritis. The disappearance of H. pylori antibodies is accompanied by no or more than a mild improvement of the gastric mucosa.
We report here the case of a 58-year-old asymptomatic male smoker who had a gastroscopy performed in 1990 because of a low serum pepsinogen I level (16 microg/l). The patient had severe atrophic corpus gastritis and elevated Helicobacter pylori antibody titers, but no histologic evidence of the bacteria. Additionally, a hiatal hernia without esophagitis was seen. He was followed up endoscopically because of the atypical changes (indefinite for dysplasia) in addition to atrophic gastritis in some of the gastric biopsy samples. During the follow-up period, H. pylori antibody titers declined to normal levels without eradication therapy, and atrophic gastritis healed. The patient developed first erosive esophagitis, and, 5 years later, a 3-cm-long Barrett's esophagus was detected.
OBJECTIVE: A causal relationship between Helicobacter pylori (H. pylori) and peptic ulcer complications remains obscure. The aim of this study was to determine the importance of H. pylori and other risk factors for healing rate, ulcer recurrence, and rebleeding in patients with bleeding peptic ulcer. METHOD: A total of 223 patients with H. pylori positive bleeding peptic ulcer were randomly allocated to three treatment groups: 1) quadruple therapy (QT) (88 patients); 2) dual therapy (DT) (88 patients); and 3) omeprazole and placebo therapy (OPl) (47 patients). Endoscopic assessment was performed initially and at 8 and 52 wk. Ulcer healing and eradication rates were assessed; endpoints were ulcer relapse and ulcer rebleeding during 52 wk. RESULTS: Results after 8 and 52 wk were available for 211 and 179 patients, respectively. Eradication rate was 100% (95% CI = 96-100%) in the QT, 84% (95% CI = 74-91%) in the DT, and 4% (95% CI = 1-15%) in the OPl group. Ulcer healing rate was 95% (95% CI = 91-98%) in H. pylori negative and 8% (95% CI = 70-91%) in H. pylori positive patients. Ulcer relapses occurred in 2% (95% CI = 0.5-6%) of H. pylori negative and in 38% (95% CI = 24-54%) of H. pylori positive patients, and rebleeding occurred in five patients (three H. pylori positive and two negative). CONCLUSIONS: Eradication of H. pylori infection enhances healing of bleeding peptic ulcers after endoscopic therapy. H. pylori infection is an important independent risk factor for relapsing of nonbleeding ulcers in patients with bleeding peptic ulcer.
Intestinal (IGCA) and diffuse (DGCA) gastric adenocarcinomas, the two main microscopic subtypes, are dissimilar regarding their epidemiological and demographic characteristics. Both tumor types comprise approximately 40% of all gastric adenocarcinomas. The DGCAs more often occur in young age groups, more often affect the corpus, and are less infrequently associated with atrophic gastritis and intestinal metaplasia than the IGCAs. The risk of both DGCA and IGCA is increased in the presence of Helicobacter pylori infection, and the risk rises with increases in grade and extent of atrophic gastritis and intestinal metaplasia. It is likely that the development of up to 80% of the DGCAs and IGCAs can be prevented with early eradication of the H. pylori infection. The pathogenesis and morphogenesis of DGCAs are unknown, but the morphogenesis of IGCAs includes identifiable precancerous conditions such as atrophic gastritis and intestinal metaplasia as well as identifiable precancerous lesions (adenomas, dysplasias). Atrophic gastritis is a direct result of the H. pylori infestation. Atrophic gastritis, for unknown reasons, appears in more than half of the infected subjects during their lifetime. H. pylori gastritis triggers a variety of reactions, with the reaction cascades resulting in errors of the cell genome and ending up as neoplastic tumors.