Association between Gastric Cancer Risk and Serum Helicobacter pylori Antibody Titers

A Novel Index Including Age, Sex, hTERT, and Methylated RUNX3 Is Useful for Diagnosing Early Gastric Cancer

INTRODUCTION

As the incidence of gastric cancer (GC) is increasing in East Asia including Japan, a simple blood test for early GC is needed as an alternative to upper gastrointestinal (UGI) endoscopy. We performed this study to address this issue.

METHODS

We collected serum samples from 319 participants comprising 225 healthy subjects without GC (control group) and 94 patients with early GC (early GC group). After evaluating copy numbers of serum hTERT and methylated RUNX3 (m-RUNX3) using the Combined Restriction Digital PCR (CORD) assay, which we developed, we assessed the diagnostic performance of hTERT and m-RUNX3 for early GC.

RESULTS

Serum levels of hTERT and m-RUNX3 were significantly higher in the early GC group than in the control group. The area under the curve (AUC) was 0.89 for hTERT and 0.78 for m-RUNX3. Multivariate logistic regression analysis revealed age, sex, hTERT copy number, and m-RUNX3 copy number to be independent factors for early GC. We then established a prediction formula and named it the ASTEm-R3 (age, sex, hTERT, and m-RUNX3) index. The AUC of the ASTEm-R3 index was 0.93 with a sensitivity of 79.7% and specificity of 91.1%.

CONCLUSION

We demonstrated excellent performance of the ASTEm-R3 index using the CORD assay to detect early GC. This index might be a promising alternative to UGI endoscopy.

INTRODUCTION

As the incidence of gastric cancer (GC) is increasing in East Asia including Japan, a simple blood test for early GC is needed as an alternative to upper gastrointestinal (UGI) endoscopy. We performed this study to address this issue.

METHODS

We collected serum samples from 319 participants comprising 225 healthy subjects without GC (control group) and 94 patients with early GC (early GC group). After evaluating copy numbers of serum hTERT and methylated RUNX3 (m-RUNX3) using the Combined Restriction Digital PCR (CORD) assay, which we developed, we assessed the diagnostic performance of hTERT and m-RUNX3 for early GC.

RESULTS

Serum levels of hTERT and m-RUNX3 were significantly higher in the early GC group than in the control group. The area under the curve (AUC) was 0.89 for hTERT and 0.78 for m-RUNX3. Multivariate logistic regression analysis revealed age, sex, hTERT copy number, and m-RUNX3 copy number to be independent factors for early GC. We then established a prediction formula and named it the ASTEm-R3 (age, sex, hTERT, and m-RUNX3) index. The AUC of the ASTEm-R3 index was 0.93 with a sensitivity of 79.7% and specificity of 91.1%.

CONCLUSION

We demonstrated excellent performance of the ASTEm-R3 index using the CORD assay to detect early GC. This index might be a promising alternative to UGI endoscopy.

Analyses of the association between Helicobacter pylori antibody titre and pathogenicity before and after eradication: results of the Kyushu and Okinawa population study, a retrospective observational cohort study

OBJECTIVES

To assess the utility of Helicobacter pylori antibody testing, we evaluated the correlation between the H. pylori antibody titre and H. pylori-associated pathogenicity and the changes in antibody titre after H. pylori eradication therapy.

DESIGN

A retrospective observational cohort study.

SETTING AND PARTICIPANTS

From 2004 to 2016, medical check-ups were performed in different regions of Japan. In total, 324 subjects infected with H. pylori who received H. pylori eradication therapy were enrolled; H. pylori was eradicated in 266 of these subjects. We examined the associations between H. pylori antibody titre with pepsinogen and the presence or absence of H. pylori-associated pathogenic proteins, such as cytotoxin-associated gene A and vacuolating cytotoxin gene A, at baseline and after H. pylori eradication therapy.

RESULTS

The H.pylori antibody titre showed a positive correlation with pepsinogen II and a negative correlation with the pepsinogen I/II ratio. Moreover, the H.pylori antibody titre significantly correlated with the positive rates of H. pylori-associated pathogenic protein before eradication therapy. Antibody titres decreased after eradication, the pepsinogen I/II ratio increased and the H. pylori-associated pathogenic protein-positive rate decreased in patients with successful eradication. The determination of eradication using the decline in antibody titre 6 months after eradication therapy was useful (area under the receiver operating characteristic curve: 0.98).

CONCLUSIONS

Our data indicate that the H. pylori antibody titre may represent the degree of pathogenicity. The H. pylori antibody titre was associated with attenuation of pathogenicity in patients with H. pylori eradication, indicating the clinical utility of H. pylori antibody testing.

Diagnostic performance of the normal range of gastrin calculated using strict criteria based on a combination of serum markers and pathological evaluation for detecting gastritis: a retrospective study

BACKGROUND

The ABC method, which combines the pepsinogen method and anti-Helicobacter pylori antibody titers, has been used for risk screening for gastric cancer in Japan. However, it has been reported that there are cases of gastritis and carcinogenesis risk even in group A, which is considered to be a low-risk group based on the ABC method. Currently, in group A, endoscopic examination is needed to strictly discriminate "patients without gastritis" (defined as true A patients) from those "with gastritis." A simple and minimally invasive diagnostic criterion for gastritis using serological markers is desirable. In this study, we aimed to identify the normal serum gastrin concentrations in normal stomach cases based on pathological diagnosis and investigate the usefulness of serum gastrin concentrations in diagnosing gastritis.

METHODS

Patients who underwent endoscopy and blood tests at Hiroshima University Hospital were enrolled in the study and categorized into the "pathologically-evaluated group" and "endoscopically-evaluated group," according to the evaluation method of atrophic gastritis. Initially, we measured serum gastrin concentrations in the normal stomach cases in the pathologically-evaluated group and calculated the normal range of serum gastrin concentrations. We used the upper limit of this normal range of serum gastrin concentrations and performed a validation study to determine its usefulness as a diagnostic marker for distinguishing between cases of gastritis and true A in the endoscopically-evaluated group.

RESULTS

The 95th percentile of serum gastrin concentrations in pathologically-evaluated normal stomach cases was 34.12-126.03 pg/mL. Using the upper limit of this normal range of serum gastrin concentrations, the sensitivity, specificity, positive predictive value, and negative predictive value for gastritis were 52.8%, 92.6%, 97.0%, and 31.0%, respectively. Additionally, the receiver operating characteristic (ROC) curve for the endoscopically-evaluated group showed an area under the ROC curve of 0.80.

CONCLUSION

The gastrin cut-off value of 126 pg/mL has a good positive predictive value (97.0%) for detecting gastritis positing its use as a marker for cases requiring endoscopy. However, the identification of patients with gastritis having normal serum gastrin concentrations due to insufficient sensitivity remains a challenge for the future.

Identification of serum microRNAs as potential diagnostic biomarkers for detecting precancerous lesions of gastric cancer

Aim

Gastric mucosal changes associated with chronic gastritis are known to be precancerous lesions of gastric cancer. We aimed to identify individuals with a high risk of gastric cancer by detection of microRNAs (miRNA) in the blood as biomarkers.

Methods

Of 1206 individuals screened, 144 who were positive for Helicobacter pylori (H. pylori) by the serum antibody test and who underwent endoscopy were the subjects of this study. For the gross assessment of mucosal inflammation, we applied the Kimura-Takemoto classification, in which normal mucosa was defined as grade 0, and atrophy was categorized as grade 1 (C-1 and C-2), grade 2 (C-3 and O-1), and grade 3 (O-2 and O-3). Serum samples were divided into two phases and used for miRNA microarray profiling. We compared the expression of miRNAs in grade 3 mucosa and other grades. Expression in gastric cancer was confirmed with TCGA data.

Results

miR-196b-3p was significantly upregulated, and miR-92a-2-5p was downregulated (P < .05 and q < 0.2). TCGA data showed a high expression of miR-196b-3p in gastric cancer cases (P < .001). Comparing grade 3 and the others, the area under the receiver operating characteristic curve using the detected miRNAs was as high as about 0.7. Furthermore, the combination of miRNAs resulted in higher accuracy. In terms of the significance of the combinatory mRNAs, the combination of three miRNAs (miR-196b-3p, miR-92a-2-5p, and miR-6791-3p) revealed high sensitivity and specificity, with the area under the curve exceeding 0.8.

Conclusion

The identified combinatory miRNAs may represent promising biomarkers of precancerous lesions in gastric cancer.

Helicobacter pylori infection: is there circulating vacuolating cytotoxin A or cytotoxin-associated gene A protein?

BACKGROUND

Helicobacter pylori infection is a well-recognized cause of gastric diseases, including chronic gastritis, peptic ulcer, and gastric cancer. Vacuolating cytotoxin-A (VacA) and cytotoxin-associated gene A protein (CagA) play a role in the pathogenesis of H. pylori-related gastric diseases. Also, extragastric disorders are frequent morbid complications in patients with H. pylori infection. However, the direct pathologic implication of these virulence factors in extragastric manifestations remains unclear. Our hypothesis in the present study is that VacA and CagA released by H. pylori in the gastric mucosa leak into the systemic circulation, and therefore they can be measured in serum.

RESULTS

Sixty-two subjects were enrolled. They were allocated into the H. pylori-positive and H. pylori-negative groups. VacA and CagA were measured by immunoassays. The serum levels of VacA and CagA above an upper limit cut-off (mean plus two standard deviations of the mean in patients without H. pylori infection) were considered positive for antigen circulating level. Five out of 25 H. pylori-positive patients were positive for both serum VacA and serum CagA. The serum levels of VacA and CagA were significantly correlated with the serum levels of anti- H. pylori antibody and interleukin-12p70 among all H. pylori-positive and H. pylori-negative patients.

CONCLUSIONS

This study suggests that spill-over of VacA and CagA antigens in the systemic circulation may occur in some patients with H. pylori infection.

Prevalence of Helicobacter pylori infection in the general population evaluated by a resident-register-based epidemiological study

BACKGROUND

The current status of Helicobacter pylori infection in Japan has not been investigated. We evaluated the status of H. pylori infection in a Japanese general population using large-scale resident-register-based sampling.

METHODS

All 6069 adults in a rural town and 6000 adults in two urban cities (3000 each), selected by register-based random sampling, were enrolled in our health check-up program. Antibody titers against Helicobacter pylori (cut-off value was 3 U/mL by Eiken E-plate) were evaluated, and subjects with a positive result were encouraged to undergo further examinations.

RESULTS

A total of 1586 subjects participated in serum sampling. The overall prevalence of H. pylori infection was 40.0% (634/1586), and it increased with age both in rural and urban areas. Although the overall positive rate was higher in the rural area (49.4%) than in the urban areas (35.6 and 32.3%), there was no difference in H. pylori status of younger subjects between the two areas. Among 634 patients with a positive titer, 374 (59.0%) underwent further examinations including endoscopic examination, and 180/634 (28.4%) patients received eradication therapy. Gastric neoplasms (three adenocarcinomas and one adenoma) were found in our screening program.

CONCLUSION

We clarified population-based random sampling data of H. pylori infection in a Japanese general population. In younger subjects, a decrease in the prevalence of H. pylori infection was confirmed both in rural and urban areas. This provides basic information for establishing a strategy to reduce gastric cancer deaths.

Identification of Helicobacter pylori-related gastric cancer risk using serological gastritis markers and endoscopic findings: a large-scale retrospective cohort study

Background

Gastric cancer remains a severe public health problem worldwide, particularly in Japan. Recent studies have demonstrated that serum markers are beneficial for risk stratification in gastric cancer development. We aimed to evaluate the usefulness of serum markers either alone or in combination (serum markers plus endoscopy) for effective risk stratification of gastric cancer development.

Methods

We enrolled 22,736 patients aged 20–95 years who underwent blood sampling and endoscopic examination at Hiroshima University Hospital in Japan between 1990 and 2014. The serum pepsinogen (PG) levels and anti-Helicobacter pylori antibody (Hp-Ab) titers were evaluated in each patient. The enrolled patients were matched with the database of the Hiroshima Prefecture Regional Cancer Registry. We processed the medical records and excluded patients with possible confounding factors for PG levels, such as proton pump inhibitor use, prior successful eradication therapy, post-gastrectomy, severe hepatorenal dysfunction, Zollinger–Ellison syndrome, and autoimmune gastritis. Among the remaining 5131 patients, we reviewed records of endoscopic examinations and selected 1507 patients (mean age, 62.5 years; 985 men and 522 women) who underwent endoscopic examination more than three months after blood sampling.

First, based on the ABC method, patients were classified as follows: High PG levels and negative Hp-Ab, group A, high PG levels and positive Hp-Ab, group B, low PG levels and positive Hp-Ab, group C, and low PG levels and negative Hp-Ab, group D. Group A was further classified into two subgroups using endoscopic findings: true A without atrophic gastritis and pseudo A with atrophic gastritis. All patients underwent annual endoscopy follow-up.

Results

Among the 1,507 patients (mean age, 62.5 years; 985 men), 24 were diagnosed with newly developed gastric cancer. No significant difference in cancer development was found between group A (PG negative and Hp-Ab negative) and the other groups. Remarkably, no true A group subjects developed gastric cancer.

Conclusions

The combination of serum markers and endoscopic findings is essential for the risk evaluation of gastric cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02381-z.

Analysis of long-term serological and histological changes after eradication of <i>Helicobacter pylori</i>

Stratification of gastric cancer risk by measuring serological biomarkers is useful for screening of gastric cancer. However, this method has problem such as overlooking past infected patients. We aimed to evaluate the association between Helicobacter pylori infection status and serological biomarkers. We divided 5,268 patients according to Helicobacter pylori infection status and past infected patients were divided into 12 groups according to time elapsed since eradication. We analyzed mean serum H. pylori immunoglobulin G antibody, pepsinogen titers, histological and endoscopic atrophy score of each group. Mean H. pylori immunoglobulin G antibody showed a decreasing tendency, there was no significant difference from the uninfected group at 11 years after eradication (p = 0.19). PGI, PGII decreased in short term after eradication. However, both PGI and PGII gradually increased as long-term changes after eradication, became comparable to those in the uninfected group (p = 0.41, p = 0.37, respectively). Histological atrophy improved gradually, became equivalent to uninfected group. Endoscopic atrophy score did not improve for long term after eradication. In conclusion, patients with long term after eradication reach the uninfected condition serologically, histologically. Endoscopic assessment of gastric mucosal atrophy may be useful for accurate assessment of gastric cancer risk.

Feasibility of endoscopic evaluation of Helicobacter pylori infection status by using the Kyoto classification of gastritis in the population-based gastric cancer screening program: A prospective cohort study

BACKGROUND AND AIMS

We have started a new population-based endoscopic gastric cancer screening program in Kurashiki city with consideration of Helicobacter pylori infection status based on endoscopic features. We aimed to verify the feasibility of this attempt in a prospective case-registration study (UMIN000028629).

METHODS

Data were collected from 1784 subjects without past eradication of H. pylori and who underwent endoscopic gastric cancer screening in Kurashiki Central Hospital Preventive Healthcare Plaza from September 2017 to June 2018. Endoscopic judgment of H. pylori infection status was made according to the Kyoto classification of gastritis. For comparison, a combination serum test of anti-H. pylori antibody and pepsinogen I and II, the ABC method, was used.

RESULTS

The endoscopic diagnoses were nongastritis, 1215 (68.1%); active or inactive gastritis, 469 (26.3%); and undefined, 23 (1.3%). With the ABC method as a reference standard, the false-negative rate of the endoscopic judgment for H. pylori infection was 16.3% (95% confidence interval: 13.1%-20.0%). Most false-negative cases were of Group B in the ABC method, which is considered gastritis with mild mucosal atrophy. Antibody titers in this population were mostly in the weak-positive range but clinically significant elevation of the antibody suggesting current infection was observed in some cases.

CONCLUSIONS

Endoscopic diagnosis of H. pylori infection status in a population-based gastric cancer screening program is mostly reliable, but false-negative results may occur, especially in patients with mild gastric atrophy. To avoid this limitation, we recommend adding H. pylori antibody test to the program.

Blood Free-Circulating DNA Testing of Methylated RUNX3 Is Useful for Diagnosing Early Gastric Cancer

The main modalities for gastric cancer screening are limited to upper gastrointestinal endoscopy and contrast radiography. The former is invasive, and the latter has high false-negative rates. Thus, alternative diagnostic strategies are required. One solution may be a liquid biopsy. Methylated RUNX3 is a well-known biomarker of gastric cancer but it is very difficult to detect with conventional bisulfite-based methylation assays when only a small amount of serum is available. We developed the combined restriction digital PCR (CORD) assay, a new methylation assay allowing for the counting of as little as one copy of a methylated gene in a small sample of DNA without necessitating DNA bisulfite treatment. We evaluated the sensitivity and specificity of the serum DNA testing of methylated RUNX3 by the CORD assay for the detection of early gastric cancer using 50 patients with early gastric cancer and 61 control individuals. The CORD assay had a sensitivity of 50.0% and a specificity of 80.3% for early gastric cancer. Methylated RUNX3 copies were significantly associated with tumor size, massive submucosal invasion, and lymph-vascular invasion. After the treatment, the median number of methylated RUNX3 copies was significantly decreased. The CORD assay may provide an alternative screening strategy to detect even early-stage gastric cancer.

Downregulation of Interleukin- (IL-) 17 through Enhanced Indoleamine 2,3-Dioxygenase (IDO) Induction by Curcumin: A Potential Mechanism of Tolerance towards Helicobacter pylori

The anti-inflammatory and antimicrobial properties of curcumin suggest its use as an anti-Helicobacter pylori (H. pylori) agent, but mechanisms underlying its helpful activity are still not clear. Indoleamine 2,3-dioxygenase (IDO) promotes the effector T cell apoptosis by catalyzing the rate-limiting first step in tryptophan catabolism, and its high expression in H. pylori-infected human gastric mucosa attenuates Th1 and Th17 immune response. The aim of this study was to investigate the role of curcumin in modulating the expression of IL-17 and IDO in H. pylori-infected human gastric mucosa. In an organ culture chamber, gastric biopsies from 35 patients were treated with and without 200 μM curcumin. In H. pylori-infected patients (n = 21), IL-17 was significantly lower, both in gastric biopsies (p = 0.0003) and culture supernatant (p = 0.0001) while IDO significantly increased (p < 0.00001) in curcumin-treated sample compared with untreated samples. In a subgroup of H. pylori-infected patients (n = 15), samples treated with curcumin in addition to IDO inhibitor 1-methyl-L-tryptophan (1-MT) showed a higher expression of IL-17 compared with untreated samples and curcumin-treated alone (p < 0.00001). Curcumin downregulates IL-17 production through the induction of IDO in H. pylori-infected human gastric mucosa, suggesting its role in dampening H. pylori-induced immune-mediated inflammatory changes.