Gastric cancer screening by combined assay for serum anti-Helicobacter pylori IgG antibody and serum pepsinogen levels - "ABC method"

Chronic gastritis

Prevalence of chronic gastritis has markedly declined in developed populations during the past decades. However, chronic gastritis is still one of the most common serious pandemic infections with such severe killing sequelae as peptic ulcer or gastric cancer. Globally, on average, even more than half of people may have a chronic gastritis at present. Helicobacter pylori infection in childhood is the main cause of chronic gastritis, which microbial origin is the key for the understanding of the bizarre epidemiology and course of the disease. A life-long and aggressive inflammation in gastritis results in destruction (atrophic gastritis) of stomach mucosa with time (years and decades). The progressive worsening of atrophic gastritis results subsequently in dysfunctions of stomach mucosa. Atrophic gastritis will finally end up in a permanently acid-free stomach in the most extreme cases. Severe atrophic gastritis and acid-free stomach are the highest independent risk conditions for gastric cancer known so far. In addition to the risks of malignancy and peptic ulcer, acid-free stomach and severe forms of atrophic gastritis may associate with failures in absorption of essential vitamins, like vitamin B12, micronutrients (like iron, calcium, magnesium and zinc), diet and medicines.

Autoimmune gastritis in autoimmune thyroid disease

BACKGROUND

Autoimmune gastritis leads to oxyntic gastric atrophy, a condition at increased risk for gastric cancer. Autoimmune gastritis in conjunction with autoimmune thyroid disease has been reported previously.

AIM

In a case-control study in patients with autoimmune thyroid disease to evaluate the usefulness of serum pepsinogens for the identification of oxyntic gastric atrophy, and to determine the relationship of Helicobacter pylori with oxyntic gastric atrophy.

METHODS

Patients with autoimmune thyroid disease (cases) and goitre (controls) were prospectively enrolled in the study. Pepsinogen (PG) I levels ≤25 μg/mL and PG I/II ratio ≤3 were indicative for oxyntic gastric atrophy. Antibodies against H. pylori, CagA and parietal cells were also determined. Esophagogastroduodenoscopy with biopsies was offered to patients with serological oxyntic gastric atrophy.

RESULTS

In total, 34 autoimmune thyroid disease patients and 30 controls were enrolled. Serological oxyntic gastric atrophy was present only in autoimmune thyroid disease patients (8/34, 23.5%, OR 8.3, 95% CI = 1.9-36.2). In all eight patients oxyntic gastric atrophy was confirmed by histology. OLGA stage I, II, III and IV was described in 0%, 33%, 50% and 17% of the cases, respectively. About, 89% and 11% of oxyntic gastric atrophy patients were seropositive for antibodies against parietal cells or H. pylori infection, respectively. Gastric atrophy involved the angulus/antrum in 50% of patients with autoimmune gastritis.

CONCLUSIONS

The seroprevalence of oxyntic gastric atrophy is high in patients with autoimmune thyroid disease, and testing of serum pepsinogens should be included in the clinical assessment of these patients. H. pylori infection is unlikely to be a principal factor in the pathogenesis of oxyntic gastric atrophy in patients with autoimmune thyroid disease. In autoimmune gastritis, gastric atrophy can spread from the oxyntic towards the antral mucosa.

Magnetically guided capsule versus conventional gastroscopy for upper abdominal complaints: a prospective blinded study

OBJECTIVES

Upper gastrointestinal endoscopy is mostly performed under sedation and has a low yield of relevant gastric lesions in patients without alarm symptoms. Simpler screening tests such as capsule endoscopy could be helpful, but gastric visualization is insufficient with the current passive capsules. A magnetically guided gastric capsule was prospectively evaluated in patients with routine indications for gastroscopy.

METHODS

A total of 189 symptomatic patients (105 male; mean age 53 y) from 2 French centers subsequently and blindly underwent capsule and conventional gastroscopy by 9 and 6 examiners, respectively. The final gold standard was unblinded conventional gastroscopy with biopsy under propofol sedation. Main outcome was accuracy (sensitivity/specificity) of capsule gastroscopy for diagnosis of major gastric lesions, defined as those lesions requiring conventional gastroscopy for biopsy or removal.

RESULTS

Twenty-three major lesions were found in 21 patients. Capsule accuracy was 90.5% [95% confidence interval (CI), 85.4%-94.3%] with a specificity of 94.1% (95% CI, 89.3%-97.1%) and a sensitivity of 61.9% (95% CI, 38%-82%). Accuracy did not correlate with lesion location, gastric luminal visibility, examiner case volume, or examination time. Of the remaining 168 patients, 94% had minor and mostly multiple lesions; the capsule made a correct diagnosis in 88.1% (95% CI, 82.2%-92.6%), with gastric visibility and lesion location in the proximal stomach having significant influence. All patients preferred capsule gastroscopy.

CONCLUSIONS

In a prospective and strictly blinded study, magnetically guided capsule gastroscopy was shown to be feasible in clinical practice and was clearly preferred by patients. Improvements in capsule technology may render this technique a future alternative to gastroscopy.

Endoscopic quality indicators for esophagogastroduodenoscopy in gastric cancer screening

BACKGROUND

Quality indicators of screening esophagogastroduodenoscopy are essential to improve the detection rate of gastric cancer. However, a reliable, practical indicator of the performance of endoscopists in screening esophagogastroduodenoscopy has not yet been identified.

AIMS

We aimed to identify quality indicators of esophagogastroduodenoscopy for the detection of early gastric neoplasms, including gastric dysplasia and early gastric cancer, focusing on the endoscopic findings.

METHODS

The records of 54,889 individuals who underwent esophagogastroduodenoscopy for gastric cancer screening at the Yonsei University Severance Hospital Health Promotion Center, Seoul, Korea, between February 2006 and July 2013 were analyzed. The detection rates for various gastric lesions including early gastric neoplasms were analyzed for each endoscopist.

RESULTS

Gastric dysplasia, early gastric cancer, and advanced gastric cancer were detected in 97 (0.18 %), 54 (0.10 %), and 21 (0.04 %) of 54,889 individuals, respectively. Multivariate analysis showed that the detection rates of gastric subepithelial lesions and gastric diverticuli were independent factors associated with the detection rate of early gastric neoplasms (regression coefficients of 0.096 and 0.532, respectively). A quality score formula was deduced using these regression coefficients to predict the ability of an endoscopist to detect early gastric neoplasms. A trend test confirmed that the group of endoscopists with a higher quality score showed a significantly higher rate of early gastric neoplasm detection (P < 0.001).

CONCLUSIONS

The detection rates of gastric subepithelial lesions and gastric diverticuli are well correlated with that of early gastric neoplasms. In addition, the proposed quality scoring system could be a good quality indicator for the detection of early gastric neoplasms.

Expression of serum let-7c, let-7i, and let-7f microRNA with its target gene, pepsinogen C, in gastric cancer and precancerous disease

This study examined the expression patterns of serum let-7 microRNA (miRNA) and its target gene, pepsinogen C (PGC), in gastric cancer (GC) and precancerous disease patients to evaluate their diagnostic efficiency for GC and its precursor and to investigate any correlation between the two. Serum samples were taken from 638 patients, including 214 GC patients, 222 atrophic gastritis (AG) patients, and 202 controls (CON). The expression of serum let-7 miRNA was detected in control-AG (precancerous disease) through to GC patients using quantitative reverse-transcription polymerase chain reaction. Serum PGC was determined by enzyme-linked immuno-sorbent assay. PGC expression in situ was detected by immunohistochemistry staining. The luciferase reporter gene system was used to verify correlation between let-7 miRNA and its predicted target gene. The results showed that serum let-7c, let-7i, and let-7f demonstrated significant differences in the CON-AG-GC sequence (P = 0.017, P < 0.001, P = 0.003, respectively); let-7c was significantly lower in the AG group, and let-7i and let-7f were significantly higher in the GC group. Significantly different expressions of serum PGC were found among the three diseases, and also between AG vs. CON, and GC vs. CON (P = 0.027, P = 0.001, respectively). Linear-regression analysis suggested that serum let-7c was negatively correlated to the expression of PGC (r = -0.096, P = 0.047), and serum let-7c, let-7i, and let-7f showed no association with PGC expression in tissue. In addition, serum let-7c, let-7f, and let-7i showed significant correlations with environment factors. Serum let-7c, let-7i, and let-7f demonstrated significant differences in the CON-AG-GC disease sequence indicating that let-7 miRNA might have value by serving as potential biomarker in the diagnosis of GC or its precancerous diseases. There were significant negative correlations between serum let-7c and its target gene PGC expression.

Implementation of gastric cancer screening - the global experience

Gastric cancer (GC) is still an important global healthcare problem, and in absolute figures it is going to remain at the present level in foreseeable future. In general, survival of patients with GC is poor mainly due to advanced-stage diagnosis. Early-stage GC can be cured by endoscopic resection or less invasive surgical treatment. Unfortunately, there is no appropriate screening strategy available for global application. This article provides a description of established national and regional GC screening programs and the screening modalities used. This review also summarizes current approaches to develop cancer-screening biomarkers. Although candidates with initial promising results have been suggested, moving discovery into clinical practice is still a major challenge. Well-designed biomarker studies, with systematic validation steps, are needed to decrease the burden of this fatal disease.

Endoscopic diagnosis of gastric mucosal atrophy: multicenter prospective study

BACKGROUND AND AIM

Gastric atrophy is one of the important pathological states that cause gastric cancer. As atrophic gastritis is related to the risk of gastric cancer, it is important to diagnose atrophic gastritis. In the present study, we tried to establish endoscopic criteria for atrophic gastritis.

METHODS

A multicenter study of prospectively collected patients was conducted in 24 participating facilities. Two hundred and seventy-five patients received endoscopic examination and 15 endoscopic features, including diffuse redness, swelling of areae gastrica, and mucosal swelling, were evaluated. Biopsy specimens were taken from five points recommended by the Updated Sydney System, and evaluated by a single pathologist for atrophy. Sensitivity, specificity, positive predictive value, negative predictive value, area under the receiver operating characteristic curve (AUC/ROC) of each endoscopic finding to histological atrophy were calculated. Pepsinogen I/II ratios of these patients were measured and compared to the endoscopic features.

RESULTS

There was no single endoscopic feature that is highly specific for histological atrophy. In the corpus, the combination of visibility of vascular pattern and swelling of areae gastrica by indigocarmine chromoendoscopy showed the highest AUC/ROC (0.83). In the antrum, the combination of visibility of vascular pattern and mucosal swelling showed the highest AUC/ROC (0.70). These endoscopic findings correlated very well to the pepsinogen I/II ratio.

CONCLUSIONS

Combination of endoscopic findings can improve diagnostic accuracy, and endoscopic diagnosis of atrophy is improved especially with new endoscopic criteria, such as swelling of areae gastrica or mucosal swelling.

Differences in the levels of gastric cancer risk factors between Nanjing and Minqing counties, China

OBJECTIVES

In Fujian Province, China, gastric cancer is one of the leading causes of mortality among all malignant tumors. Nanjing county and Minqing county are located in inland Fujian and have similar general demographics. However, the adjusted mortality rate of gastric cancer in Minqing was found to be much higher than that in Nanjing. We sought to explore factors associated with this increased risk of gastric cancer between the two counties.

METHODS

We recruited 231 and 224 residents from Nanjing and Minqing, respectively, and analyzed differences between their dietary habits, Helicobacter pylori infection rates, and concentrations of serum pepsinogen I, pepsinogen II, gastrin-17, and ratio of pepsinogen I:II.

RESULTS

Subjects in Minqing had more first-degree relatives who had been diagnosed with upper gastrointestinal tumor, more unhealthy dietary habits, a higher Helicobacter pylori positive rate, and greater proportion of abnormal serum gastrin-17 than those in Nanjing did.

CONCLUSIONS

The factors that differed between these two counties might indicate that residents in Minqing have a higher risk for developing gastric cancer than those in Nanjing do.

Virulence genes of Helicobacter pylori in the Dominican Republic

Although the incidence of gastric cancer in the Dominican Republic is not high, the disease remains a significant health problem. We first conducted a detailed analysis of Helicobacter pylori status in the Dominican Republic. In total, 158 patients (103 females and 55 males; mean age 47.1±16.2 years) were recruited. The status of H. pylori infection was determined based on four tests: rapid urease test, culture test, histological test and immunohistochemistry. The status of cagA and vacA genotypes in H. pylori was examined using PCR and gene sequencing. The overall prevalence of H. pylori infection was 58.9 %. No relationship was found between the H. pylori infection rate and the age range of 17-91 years. Even in the youngest group (patients aged <29 years), the H. pylori infection rate was 62.5 %. Peptic ulcer was found in 23 patients and gastric cancer was found in one patient. The H. pylori infection rate in patients with peptic ulcer was significantly higher than that in patients with gastritis (82.6 versus 54.5 %, P<0.01). The cagA-positive/vacA s1m1 genotype was the most prevalent (43/64, 67.2 %). Compared with H. pylori-negative patients, H. pylori-positive patients showed more severe gastritis. Furthermore, the presence of cagA was related to the presence of more severe gastritis. All CagA-positive strains had Western-type CagA. In conclusion, we found that H. pylori infection is a risk factor for peptic ulcer in the Dominican Republic. Patients with cagA-positive H. pylori could be at higher risk for severe inflammation and atrophy.

Quantitative comparisons of summary receiver operating characteristics (sROC) curves among conventional serological tumor biomarkers for predicting gastric cancer in Chinese population

The objective of this study is to quantitatively analyze the predictive strength among the conventional serological tumor biomarkers for gastric cancer in Chinese population. Thirty-three hospital-based case-control studies were searched out through Chinese databases and PubMed during 1999-2009. Gastric cancer cases and healthy volunteers or benign gastric diseases controls were detected of any of serological CA724, CA242, CEA, CA199, CA125, or CA153. Areas under the curve (AUC) and optimal Q indexes of summary receiver operating characteristics (sROC) curves were quantitatively compared. The summary positive and negative likelihood ratios (sLR + and sLR-) were pooled. Totally, 2,390 gastric cancer cases and 2,893 controls were analyzed. CA724 and CA242 both had the greatest AUCs (0.88), respectively, followed by the combination CA724 + CEA + CA199 (0.85), CA125 (0.82), CEA (0.80), and CA199 (0.76), but all of them had no statistical significance to CA153 (negative control) by Z tests, possibly due to relatively great standard errors. The results of Q index analyses were similar to those of AUCs, that CA724 and CA242 had the optimal strength. The sLR + of CA724 (16.08, 95 % confidence interval (CI) 7.86-32.86) or CA242 (11.03, 95 % CI 7.12-17.08) was strong to judge the gastric cancer status based on its positive result. The combination of CA724 + CEA + CA199 had the prior sLR- (0.33, 95 % CI 0.25-0.43) to the others. Serological CA724 or CA242 has predictive effect for screening gastric cancer and can be recommended into the screening program of population-based or symptomatic cases. However, prospective epidemiological studies are required before confirmative conclusion.

Clinical significance of quantitative PCR detection of serum miR-21 in patients with gastric cancer

AIM: To explore the significance of serum miR-21 detection for non-invasive diagnosis of gastric cancer and evaluation of surgery results.

METHODS: Serum samples from normal medical personnel, patients with antral ulcers, those with gastric inflammatory polyps, those with intestinal metaplasia, and those with gastric cancer were collected, and fluorescence quantitative PCR was used to detect miR-21 expression in the above serum samples and matched gastric tissues.

RESULTS: Serum miR-21 levels had a positive correlation with those in gastric tissues in all the subjects (r = 0.826, P < 0.001). Serum levels of miR-21 were significantly higher in patients with gastric cancer than in normal controls. Postoperative serum levels of miR-21 were significantly lower than preoperative levels in gastric cancer patients (t = 0.511, P = 0.030). Serum miR-21 levels differed significantly among the five groups of subjects (χ² = 10.841, P = 0.028).

CONCLUSION: Detection of serum miR-21 is helpful for noninvasive diagnosis of gastric cancer and evaluation of surgical effects.

Serum trefoil factor 3 is a promising non-invasive biomarker for gastric cancer screening: a monocentric cohort study in China

BACKGROUND

The search for better non-invasive biomarkers for gastric cancer remains ongoing. We investigated the predictive power of serum trefoil factor (TFF) levels as biomarkers for gastric cancer in comparison with the pepsinogen (PG) test.

METHODS

Patients with gastric cancer, chronic atrophic gastritis (CAG) or chronic non-atrophic gastritis (CNAG), and healthy people were recruited. Serum concentrations of TFFs, PG I, and PG II, as well as the presence of antibodies against Helicobacter pylori, were measured by enzyme-linked immunosorbent assays (ELISA). Receiver operating characteristics (ROC) were used to compare the predictive powers of the selected factors.

RESULTS

The serum concentrations of TFF1, TFF2, and TFF3 in the control groups were significantly lower than those in the gastric cancer group with the exception of TFF2 which was elevated in CAG. The area under the ROC curve for TFF3 was greater than that for the PG I/II ratio (0.81 vs 0.78). TFF3 also had a significantly higher predictive power for distinguishing gastric cancer than the PG test (odds ratio: 10.33 vs 2.57). Moreover, combining the serum TFF3 and PG tests for gastric cancer had better predictive power than either alone.

CONCLUSIONS

Serum TFF3 may be a better predictor of gastric cancer than the PG test, while the combined testing of serum PG and TFF3 could further improve the efficacy of gastric cancer screening.

Clinical management of Helicobacter pylori--the Japanese perspective

BACKGROUND

After the approval of health insurance coverage of eradication therapy for Helicobacter pylori-positive peptic ulcer disease (PUD) in 2000, comprehensive coverage for H. pylori infection itself was implemented in 2013.

METHODS

We did a literature search using PubMed database on the management of H. pylori infection including indications, regimens, outcomes of current eradication therapies, trends of antibiotic resistance rates and proposed third-line rescue therapy in Japan. We also collected data on changes of eradication rates in our hospital by searching electronic medical records.

RESULTS

After implementation of insurance coverage of eradication therapy for PUD, dramatic reduction of the number patients with PUD as well as spending on ulcer drug was documented. According to the current regulation, proton pump inhibitor (PPI)-based triple therapy with 2 antibiotics, amoxicillin (AMPC) plus clarithromycin, for 7 days is approved as the first-line therapy. After failure of the first-line therapy, PPI plus AMPC and metronidazole is authorized as the second line, which maintains an excellent eradication rate of over 90% in Japan. When these two therapies fail, a sitafloxacin-based therapy seems to be most promising among many rescue regimens.

CONCLUSION

Comprehensive public health insurance coverage of H. pylori infection will promote eradication in Japanese people infected with H. pylori, whose risk of developing gastric cancer has been shown to be high. It also provides us a unique opportunity to study whether the broader indications can accelerate the reduction of gastric cancer in Japan in the same way we witnessed the reduction of PUD.

Progress in diagnosis and treatment of precancerous lesions and early gastric cancer

Gastric cancer is the fourth most prevalent cancer worldwide and the second cause of cancer-related death. The 5-year survival rate for early gastric cancer after treatment is 84%-99%. Early detection and treatment of precancerous lesions are pivotal to improved patient survival. The development of various endoscopic (e.g., endoscopic ultrasound, narrowband imaging, magnifying endoscopy and chromoendoscopy), imaging and laboratory technologies has significantly improved the rate of diagnosis of early cancer and precancerous lesions. In addition, endoscopic techniques (e.g., endoscopic submucosal dissection) and minimally invasive surgery (e.g., laparoscopy) make the therapy of early cancer and precancerous lesions better and less invasive, reduce the incidence of postoperative complications, and improve the quality of life of patients after surgery.

Systematic review: serum autoantibodies in the early detection of gastric cancer

Antibodies against tumor-associated antigens have been found in serum of patients with various types of cancers and may serve as biomarkers for early detection of gastric cancer as well. This systematic review aims to give an overview about known autoantibodies and their diagnostic value in gastric cancer. We conducted a systematic literature search in two databases to identify studies which performed serological testing for autoantibodies in gastric cancer patients and controls. Data on study characteristics and results were extracted independently by two reviewers. Overall, 39 articles reporting the detection of 34 different autoantibodies met the inclusion criteria for this review. The most common antibody detection method was enzyme-linked immunosorbent assay and the most frequently assessed autoantibody was anti-p53, which was tested in 13 studies. Most antibodies were assessed in only one study and only few authors have evaluated the diagnostic value of combinations of multiple autoantibodies. For single autoantibodies, specificity was generally very high (median: 99.15%), but sensitivity was mostly rather low (median: 12.35%). For some autoantibody combinations, substantially higher sensitivity at reasonably high levels of specificity could be achieved. Development of extended and optimized multimarker panels of autoantibodies might be a promising approach for gastric cancer early detection.

Serum gastrin and the pepsinogen I/II ratio as markers for diagnosis of premalignant gastric lesions

BACKGROUND

Iran is a country with very high incidences of stomach cancer, especially in Northern parts. Here we assessed prognostic value of serum screening biomarkers among people >50 years old for early detection of precancerous lesions in a hot spot for gastric carcinoma in Guilan Province, North Iran.

METHODS

A cross- sectional population-based survey was conducted on 1,390 residents of Lashtenasha city with the mean age (SD) of 61.8 (9.02) years old (50.8% females) to assess the association of gastrin and the pepsinogen (PG) I/II ratio with premalignant gastric lesions. Blood samples were taken for CBC, blood group, and serologic exams (PGI, PGII, and gastrin 17) from each subject. Expert gastroenterologists performed upper GI endoscopy and ROC curves were generated to determine appropriate cutoff points.

RESULTS

Mean values of PGI, PGII, PGI/PGII and gastrin were significantly different between patients with and without atrophy or metaplasia (P<0.05). To diagnose atrophy and intestinal metaplasia, a significantly higher AUC was observed for the PGI/PGII ratio (70 and 72%, respectively) compared to the PGI (56, 55%), PGII (63, 64%) and gastrin (59, 61%) (all p<0.001).

CONCLUSIONS

Biomarker tests such as the PGI/II ratio can be used in the screening and diagnosis of subjects at high gastric cancer risk in our region.

Advanced method for evaluation of gastric cancer risk by serum markers: determination of true low-risk subjects for gastric neoplasm

BACKGROUND

Patients with negative anti-Helicobacter pylori antibody titer and high pepsinogen (PG) level (group A) are regarded as having a low risk for gastric cancer. However, gastric cancer cases are occasionally observed in this group. We aimed to elucidate the clinical features of gastric neoplasm in group A patients and reviewed advanced methods for mass screening.

MATERIALS AND METHODS

A total of 271 gastric epithelial neoplasm patients were enrolled. We classified them according to the H. pylori-PG system and determined the number of patients in each group. After excluding true H. pylori-negative cases from group A (group A'), we examined the differences between group A' and group non-A.

RESULTS

Group A included 30 (11%) patients, and only three of these were true negative for H. pylori. All patients in group A' (n = 27) exhibited endoscopic atrophy in the gastric corpus. Serologically, these patients showed low gastrin, low PG II and high PG I/II ratio, indicative of post-eradication. Histologically, 24 (89%) of these had little inflammation, and 26 (96%) were negative for H. pylori by immunohistochemistry. No difference was observed in the incidence of metachronous gastric tumors between group A' and group non-A. The discriminant function using gastrin and PGs could distinguish these 27 patients from true H. pylori-negative controls with 85% sensitivity and 84% specificity.

CONCLUSIONS

Group A included a certain number of patients with atrophic gastritis who were potentially at risk of gastric neoplasm development. Although evaluation of corpus atrophy is necessary for the identification of these patients, the discriminant function may be useful.

Serum Helicobacter pylori CagA antibody titer as a useful marker for advanced inflammation in the stomach in Japan

BACKGROUND AND AIM

Subjects infected with Helicobacter pylori containing cagA do not always induce serum CagA antibody. Our previous meta-analysis showed that serum CagA seropositivity was associated with gastric cancer even in East Asian countries. However, it remains unclear why serum CagA-positive status is associated with gastric cancer. In this study, we aimed to examine the relationship between anti-CagA antibody titer and the levels of pepsinogen (PG), and histological score.

METHODS

Eighty-eight H. pylori-positive Japanese patients with gastritis were included. Serum CagA antibody titer, PG I, and PG II were evaluated by ELISA. Histological scores were evaluated according to Update Sydney System. CagA expression was examined by immunoblot.

RESULTS

Seroprevalence of CagA antibody was found in 75.0%. Interestingly, serum CagA antibody titer was significantly correlated with PG I and PG II levels (P = 0.003 and 0.004, respectively). Serum CagA antibody titer was also significantly correlated with mucosal inflammation in the corpus (P = 0.04). On the other hand, bacterial density was not related with CagA antibody titer. CagA expression level of the strains was irrespective of the status of PG and serum CagA antibody.

CONCLUSIONS

Subjects with higher serum CagA antibody titer can be considered as high-risk population for the development of gastric cancer from the point of strong gastric inflammatory response even in Japan. Host recognition rather than bacterial colonization might be associated with the difference of serum CagA antibody titer.

Identification of serum miRNAs as novel non-invasive biomarkers for detection of high risk for early gastric cancer

BACKGROUND

Many micro-RNAs (miRNAs) are differentially expressed in Helicobacter pylori-infected gastric mucosa and in gastric cancer tissue and previous reports have suggested the possibility of serum miRNAs as complementary tumour markers. The aim of the study was to investigate serum miRNAs and pepsinogen levels in individuals at high risk for gastric cancer both before and after H. pylori eradication.

METHODS

Patients with recent history of endoscopic resection for early gastric cancer and the sex- and age-matched controls were enrolled. Serum was collected from subjects before or after eradication and total RNA was extracted to analyse serum levels of 24 miRNAs. Serum pepsinogen (PG) I and II levels were measured using enzyme-linked immunosorbent assay kits.

RESULTS

Using miR-16 as an endogenous control, the relative levels of miR-106 and let-7d before and after H. pylori eradication and miR-21 after eradication were significantly higher in the high-risk group than in the controls. H. pylori eradication significantly decreased miR-106b levels and increased let-7d only in the control group. After eradication, the combination MiR-106b with miR-21 was superior to serum pepsinogen and the most valuable biomarker for the differentiating high-risk group from controls.

CONCLUSION

Serum miR-106b and miR-21 may provide a novel and stable marker of increased risk for early gastric cancer after H. pylori eradication.

Polymorphisms in genes coding for HSP-70 are associated with gastric cancer and duodenal ulcer in a population at high risk of gastric cancer in Costa Rica

BACKGROUND AND AIMS

Costa Rica has among the highest incidence and mortality rates for gastric cancer worldwide. The reasons for this are largely unknown. Polymorphisms of inflammatory response genes including genes encoding heat shock proteins (HSP) have been shown to be associated with the risk of gastric cancer in some populations. This study addresses the possible association between the HSP70-2 +1267 and HSP70-Hom +2437 polymorphisms and the risk of developing gastric cancer in a high-risk population in Costa Rica.

METHODS

DNA from 39 individuals diagnosed with gastric cancer, 79 healthy controls, 55 individuals with chronic gastritis and 52 individuals with duodenal ulcer was genotyped for the polymorphisms HSP70-2 +1267 and HSP70-Hom +2437 by RFLP. Logistic regression analysis was used to determine possible associations with the diagnoses and lineal regression analysis to determine associations with blood pepsinogen (PGs) levels as measured by serology.

RESULTS

The GA genotype of HSP70-2 was associated with increased risk of gastric cancer (OR = 3.42; 95% CI = 1.27-9.21; p = 0.015) and duodenal ulcer (OR = 2.57; 95% CI = 1.03-6.36; p = 0.042) as compared to the GG genotype. Persons with C carrier genotypes of HSP70-Hom were significantly less susceptible to gastric cancer than those with the TT genotype (OR = 0.29; 95% CI = 0.09-0.87; p = 0.027). The C carrier genotype was associated with lower PGI concentrations but none of the polymorphisms were associated with PGI/PGII.

CONCLUSIONS

Polymorphisms of HSP70 genes are associated with the development of gastric cancer and duodenal ulcers in a population at high risk for gastric cancer in Costa Rica.

Eradication of gastric cancer is now both possible and practical

In 1994, Helicobacter pylori was declared a human carcinogen. Evidence has now accumulated to show that at least 95% of gastric cancers are etiologically related to H. pylori. An extensive literature regarding atrophic gastritis and its effects on acid secretion, gastric microflora, and its tight association with gastric cancer has been rediscovered, confirmed, and expanded. Methods to stratify cancer risk based on endoscopic and histologic findings or serologic testing of pepsinogen levels and H. pylori testing have been developed producing practical primary and secondary gastric cancer prevention strategies. H. pylori eradication halts progressive mucosal damage. Cure of the infection in those with non-atrophic gastritis will essentially prevent subsequent development of gastric cancer. For all, the age-related progression in cancer risk is halted and likely reduced as eradication reduces or eliminates mucosal inflammation and reverses or reduces H. pylori-associated molecular events such aberrant activation-induced cytidine deaminase expression, double strand DNA breaks, impaired DNA mismatch repair and aberrant DNA methylation. Those who have developed atrophic gastritis/gastric atrophy however retain some residual risk for gastric cancer which is proportional to the extent and severity of atrophic gastritis. Primary and secondary cancer prevention starts with H. pylori eradication and cancer risk stratification to identify those at higher risk who should also be considered for secondary cancer prevention programs. Japan has embarked on population-wide H. pylori eradication coupled with surveillance targeted to those with significant remaining risk. We anticipate that countries with high gastric cancer burdens will follow their lead. We provide specific recommendations on instituting practical primary and secondary gastric cancer prevention programs as well identifying research needed to make elimination of gastric cancer both efficient and cost effective.

Seroprevalence of Helicobacter pylori infection and gastric mucosal atrophy in Bhutan, a country with a high prevalence of gastric cancer

Gastric cancer is the second leading cause of cancer-related mortality in the world. Recently, serum Helicobacter pylori antibodies and pepsinogen (PG) have been used for gastric cancer screening. The incidence of gastric cancer in Bhutan is reported to be quite high compared with that in neighbouring countries. In this study, 381 subjects from three areas of Bhutan were assessed for gastric mucosal atrophy and serological parameters. Anti-H. pylori IgG, PG I, PG II and cytotoxin-associated gene A (CagA) antibodies were measured using ELISA. Subjects were classified into four groups according to H. pylori and PG seropositivity: Group A (H. pylori-negative/PG-negative), Group B (H. pylori-positive/PG-negative), Group C (H. pylori-positive/PG-positive) and Group D (H. pylori-negative/PG-positive). The prevalence of H. pylori in the 381 subjects was 71.1% (271/381), with high infection rates found in rural areas. The PG I/II ratio was significantly inversely correlated with the atrophy score in the antrum and the corpus (P<0.001). Multivariate analysis showed that the PG status was significantly associated with the presence of atrophy in the corpus. The prevalence of the PG-positive status was significantly higher among H. pylori-positive subjects than among H. pylori-negative subjects (P<0.001). Based on the ABC method, Group B was the most dominant, followed by Group A, Group C and Group D. The high incidence of gastric cancer in Bhutan can be attributed to the high prevalence of H. pylori infection and gastric mucosal atrophy.

Relationship between endoscopic and histologic gastric atrophy and intestinal metaplasia

BACKGROUND

The severity of endoscopic gastric atrophy (EGA), high-stage Operative Link on Gastritis Assessment (OLGA) gastritis (i.e., stage III or IV), and extensive intestinal metaplasia (IM) with incomplete subtype have been separately reported as high-risk factors of gastric cancer (GC). The aim of this study was to evaluate the associations between these endoscopic and pathologic characteristics.

MATERIALS AND METHODS

A cross-sectional study was conducted on 280 patients with functional dyspepsia at the University Medical Center at Ho Chi Minh City, Vietnam. Biopsies were taken according to the updated Sydney System. EGA was assessed according to the Kimura-Takemoto classification, and gastritis stage was assessed according to the OLGA system.

RESULTS

All of patients with high-stage OLGA gastritis (i.e., stage III or IV) clustered in the subgroup of patients with moderate-to-severe EGA: 13/126 (10.3%) in patients with moderate-to-severe EGA versus 0/154 (0%) in patients with none-to-mild EGA (p < .001). Moderate-to-severe EGA was also significantly associated with extensive IM (p < .001, OR = 28.1 (CI 95% 6.4-173.3)) and incomplete IM subtype (p < .001, OR = 36.7 (CI 95% 5.1-742.1). Extensive IM was also associated with incomplete IM subtype (p = .01).

CONCLUSIONS

High-stage OLGA gastritis, extensive IM with incomplete subtype clustered in patients with moderate-to-severe EGA. Assessing the severity of EGA could potentially help to identify patients who should be taken systemic biopsy for evaluating GC risk.

Structure and function studies on enzymes with a catalytic carboxyl group(s): from ribonuclease T1 to carboxyl peptidases

A group of enzymes, mostly hydrolases or certain transferases, utilize one or a few side-chain carboxyl groups of Asp and/or Glu as part of the catalytic machinery at their active sites. This review follows mainly the trail of studies performed by the author and his colleagues on the structure and function of such enzymes, starting from ribonuclease T1, then extending to three major types of carboxyl peptidases including aspartic peptidases, glutamic peptidases and serine-carboxyl peptidases.

Serum pepsinogen II is a better diagnostic marker in gastric cancer

AIM

To investigate screening makers for gastric cancer, we assessed the association between gastric cancer and serum pepsinogens (PGs).

METHODS

The subjects comprised 450 patients with gastric cancer, 111 individuals with gastric atrophy, and 961 healthy controls. Serum anti-Helicobacter pylori (H. pylori) immunoglobulin G (IgG), PGI and PG II were detected by enzyme-linked immunosorbent assay. Gastric atrophy and gastric cancer were diagnosed by endoscopy and histopathological examinations. Odds ratios and 95%CIs were calculated using multivariate logistic regression.

RESULTS

Rates of H. pylori infection remained high in Northeastern China. Rates of H. pylori IgG positivity were greater in the gastric cancer and gastric atrophy groups compared to the control group (69.1% and 75.7% vs 49.7%, P < 0.001). Higher levels of PG II (15.9 μg/L and 13.9 μg/L vs 11.5 μg/L, P < 0.001) and lower PGI/PG II ratio (5.4 and 4.6 vs 8.4, P < 0.001) were found in patients with gastric cancer or gastric atrophy compared to healthy controls, whereas no correlation was found between the plasma PGI concentration and risk of gastric cancer (P = 0.537). In addition, multivariate logistic analysis indicated that H. pylori infection and atrophic gastritis were independent risk factors for gastric cancer. Lower plasma PGI/PG II ratio was associated with higher risks of atrophy and gastric cancer. Furthermore, plasma PG II level significantly correlated with H. pylori-infected gastric cancer.

CONCLUSION

Serum PG II concentration and PGI/PG II ratio are potential biomarkers for H. pylori-infected gastric disease. PG II is independently associated with risk of gastric cancer.

Prevalence of Helicobacter pylori infection and atrophic gastritis in Latvia

OBJECTIVES

Helicobacter pylori infection and atrophic gastritis are related to an increased risk for gastric cancer. There is a decrease in global H. pylori prevalence. We analyzed the prevalence of H. pylori infection in Latvia by the plasma IgG test and the presence of atrophy by means of pepsinogen testing.

METHODS

This subanalysis was carried out on a randomly selected cross-sectional sample of a general population of adults to access cardiovascular risk factors. Plasma samples were screened for H. pylori IgG (cutoff value 24 U/ml), and pepsinogens (Pg) I and II. Pg cutoff values of PgI/PgII ≤ 3 and PgI ≤ 70 ng/ml were used to assess the prevalence of atrophy of any grade and PgI/PgII ≤ 2 and PgI ≤ 30 ng/ml for advanced atrophy.

RESULTS

Altogether, 3564 serum samples were available for the study (2346 women, 1218 men; median age 54 years). Of the tested individuals, 79.21% were H. pylori positive, with no difference between sexes. The prevalence increased with age (P<0.001). Atrophy of any grade was identified in 1444 individuals (40.52%) and advanced atrophy in 475 individuals (13.33%). Linear association with age was present in both response types (P<0.001). The prevalence of atrophy of any grade was higher in women (41.73%) than in men (38.18%; P=0.04); this difference was lost for advanced atrophy (women 13.98%, men 12.07%; P=0.1).

CONCLUSION

The prevalence of H. pylori infection or atrophy remains high in Latvia. Determining the right cutoff value is critically important for pepsinogen-based atrophy detection in Europe in order to objectively stratify gastric cancer risk.

Recent development of gastric cancer prevention

A mass screening program using photofluorography has been used as a secondary prophylaxis of gastric cancer in Japan. However, we are at a turning point for reconsidering the strategy of gastric cancer prevention because of various problems with photofluorography. The shift from current secondary prophylaxis to primary prophylaxis is now required. After a Japanese multicenter randomized controlled trial showed that Helicobacter pylori eradication reduced the incidence of metachronous gastric cancer after endoscopic resection of early gastric cancer, primary prophylaxis of gastric cancer has gained greater attention. The combination of H. pylori eradication as a primary prophylaxis and screening as a secondary prophylaxis is necessary for the elimination of gastric cancer in Japan. The strategy of test, treat and screening for H. pylori infection is effective in reducing the incidence and mortality of gastric cancer in communities with a high incidence of gastric cancer. We have proposed a program of risk stratification based on the presence of H. pylori infection with or without atrophic gastritis followed by targeted interventions.