Correlation between the ABC classification and radiological findings for assessing gastric cancer risk

The therapeutic potential value of Cancer-testis antigens in immunotherapy of gastric cancer

Gastric cancer (GC) is the fourth most common cause of mortality and the fifth for incidence, globally. Diagnosis, early prognosis, and therapy remains challenging for this condition, and new tumor-associated antigens are required for its detection and immunotherapy. Cancer-testis antigens (CTAs) are a subfamily of tumor-associated antigens (TAAs) that have been identified as potential biomarkers and targets for cancer immunotherapy. The CTAs-restricted expression pattern in tumor cells and their potential immunogenicity identify them as attractive target candidates in CTA-based diagnosis or prognosis or immunotherapy. To date, numerous studies have reported the dysregulation of CTAs in GC. Several clinical trials have been done to assess CTA-based immunotherapeutic potential in the treatment of GC patients. NY-ESO-1, MAGE, and KK-LC-1 have been used in GC clinical trials. We review recent studies that have investigated the potential of the CTAs in GC regarding the expression, function, aggressive phenotype, prognosis, and immunological responses as well as their possible clinical significance as immunotherapeutic targets with a focus on challenges and future interventions.

Gastric Cancer Screening in Japan: A Narrative Review

Gastric cancer is the second leading cause of cancer incidence in Japan, although gastric cancer mortality has decreased over the past few decades. This decrease is attributed to a decline in the prevalence of H. pylori infection. Radiographic examination has long been performed as the only method of gastric screening with evidence of reduction in mortality in the past. The revised 2014 Japanese Guidelines for Gastric Cancer Screening approved gastric endoscopy for use in population-based screening, together with radiography. While endoscopic gastric cancer screening has begun, there are some problems associated with its implementation, including endoscopic capacity, equal access, and cost-effectiveness. As H. pylori infection and atrophic gastritis are well-known risk factors for gastric cancer, a different screening method might be considered, depending on its association with the individual's background and gastric cancer risk. In this review, we summarize the current status and problems of gastric cancer screening in Japan. We also introduce and discuss the results of gastric cancer screening using H. pylori infection status in Hoki-cho, Tottori prefecture. Further, we review risk stratification as a system for improving gastric cancer screening in the future.

Higher proportions of a healthy gastric mucosa in healthy Japanese adults with later birth year: analysis of 41 957 participants

BACKGROUND

In Japan, most gastric cancers are associated with gastric mucosal atrophy caused by chronic infection with Helicobacter pylori (H. pylori). Recognizing the condition of the gastric mucosa and determining the infection status of H. pylori are important for predicting the individual risk of gastric cancer. This study aimed to determine the proportion of Japanese adults with a healthy gastric mucosa (without H. pylori infection) among 12 birth-year groups encompassing 1935-1990 by morphological images.

METHODS

The gastric mucosa was classified as healthy or having gastritis based on routine double-contrast upper gastrointestinal barium X-ray radiography. The participants included 41 957 healthy Japanese adults. Serum or urine H. pylori antibody levels were also assessed.

RESULTS

In total, 25 424 participants had healthy mucosa without a history of H. pylori eradication. The proportions of participants with a healthy mucosa by birth year were 19.8% (57/288), 27.1% (306/1128), 32.4% (569/1756), 37.6% (1808/4811), 49.2% (3207/6522), 60.1% (3966/6550), 71.2% (5224/7342), 77.2% (5114/6624), 80.6% (3342/4149), 85.0% (1404/1652), 85.3% (302/354) and 94.7% (125/132) in 1935, 1940, 1945, 1950, 1955, 1960, 1965, 1970, 1975, 1980, 1985 and after 1990, respectively (P for trend <0.01). All the participants with a healthy mucosa showed negative results in the H. pylori antibody tests.

CONCLUSIONS

The proportion of participants with normal gastric mucosa linearly increased with the birth years. The prevalence of morphologically healthy gastric mucosa could have consistently increased with decreasing prevalence of H. pylori infection.

Usefulness and Limitations of a Serum Screening System to Predict the Risk of Gastric Cancer

Objective The aim of the present study was to evaluate the effectiveness and limitations of a serum screening system for predicting the risk of gastric cancer. Methods Serum pepsinogen I (PG I)/pepsinogen II (PG II) and Helicobacter pylori (HP) antibody levels were measured. Subjects were classified into four groupsaccording to their serological status (the ABC classification system). The grade of atrophic gastritis was assessed endoscopically. We evaluated gastric cancer detection rates according to the ABC classification system and the endoscopic grade of atrophy. Patients Individuals who underwent esophagogastroduodenoscopy (EGD) in a health check were prospectively enrolled in the present study. Results According to the ABC classification system, the gastric cancer detection rates in groups A, B, C, and D were 0.07% (4/6,105), 0.5% (8/1,739), 0.8% (16/2,010), and 1.1% (3/281), respectively. The gastric cancer detection rates in subjects with no atrophy, closed type (C-type) atrophy, and open type (O-type) atrophy were 0% (0/4,567), 0.2% (4/2,581), and 0.9% (27/2,987), respectively. In group A (HP(-)/PG(-)), the proportions of subjects with no atrophy, C-type atrophy, and O-type atrophy were 71.2%, 22.8%, and 6.0%, respectively. In group A, the gastric cancer detection rates in subjects with no atrophy, C-type atrophy, and O-type atrophy were 0%, 0.07%, and 0.8%, respectively. Conclusion The ABC classification system is useful for predicting the risk of gastric cancer. However, this system was limited in group A, which included individuals with a high risk of developing gastric cancer. An endoscopic diagnosis of atrophy may be more effective than the ABC classification system for predicting the risk of gastric cancer.

Treatment strategies and preventive methods for drug-resistant Helicobacter pylori infection

The infection and drug resistance rates of Helicobacter pylori (H. pylori) are high and must be prevented and treated by better strategies. Based on recent research advances in this field as well as the results from our team and those on traditional Chinese medicine, we review the causes of drug resistance, and prevention and treatment strategies for drug-resistant H. pylori infection, with an aim to make suggestions for the development of new drugs, such as establishment of new target identification and screening systems, modification of existing drug structures, use of new technologies, application of natural products, and using a commercial compound library. This article may provide reference for eradication of drug-resistant H. pylori.

Guidelines for the management of Helicobacter pylori infection in Japan: 2016 Revised Edition

BACKGROUND

Since "Helicobacter pylori (H. pylori) infection" was set as the indication in the Japanese Society for Helicobacter Research (JSHR) Guidelines 2009, eradication treatment for H. pylori gastritis is covered under insurance since 2013 in Japan, and the number of H. pylori eradication has rapidly increased. Under such circumstances, JSHR has made the third revision to the "Guidelines for diagnosis and treatment of H. pylori infection" for the first time in 7 years.

METHODS

The Guideline Committee held 10 meetings. Articles published between the establishment of the 2009 Guidelines and March 2016 were reviewed and classified according to the evidence level; the statements were revised on the basis of this review. After inviting public comments, the revised statements were finalized using the Delphi method.

RESULTS

There was no change in the basic policy that H. pylori infectious disease is an indication for eradication. Other diseases presumed to be associated with H. pylori infection were added as indications. Serum pepsinogen level, endoscopic examination, and X-ray examination were added to the diagnostic methods. The effects of 1-week triple therapy consisting of potassium-competitive acid blocker (P-CAB), amoxicillin, and clarithromycin have improved, and high eradication rates can also be expected with proton pump inhibitors (PPI) or P-CAB combined with amoxicillin and metronidazole. If the susceptibility test is not performed, the triple PPI or P-CAB/amoxicillin/metronidazole therapy should be chosen, because the PPI/amoxicillin/metronidazole combination demonstrated a significantly higher eradication rate than PPI/amoxicillin/clarithromycin. In the proposal for gastric cancer prevention, we divided gastric cancer prevention measures by age from adolescent to elderly, who are at an increased gastric cancer risk, and presented measures for gastric cancer prevention primarily based on H. pylori eradication.

CONCLUSION

We expect the revised guidelines to facilitate appropriate interventions for patients with H. pylori infection and accomplish its eradication and prevention of gastric cancer.

Detection of gastritis by a deep convolutional neural network from double-contrast upper gastrointestinal barium X-ray radiography

BACKGROUND

Deep learning has become a new trend of image recognition tasks in the field of medicine. We developed an automated gastritis detection system using double-contrast upper gastrointestinal barium X-ray radiography.

METHODS

A total of 6520 gastric X-ray images obtained from 815 subjects were analyzed. We designed a deep convolutional neural network (DCNN)-based gastritis detection scheme and evaluated the effectiveness of our method. The detection performance of our method was compared with that of ABC (D) stratification.

RESULTS

Sensitivity, specificity, and harmonic mean of sensitivity and specificity of our method were 0.962, 0.983, and 0.972, respectively, and those of ABC (D) stratification were 0.925, 0.998, and 0.960, respectively. Although there were 18 false negative cases in ABC (D) stratification, 14 of those 18 cases were correctly classified into the positive group by our method.

CONCLUSIONS

Deep learning techniques may be effective for evaluation of gastritis/non-gastritis. Collaborative use of DCNN-based gastritis detection systems and ABC (D) stratification will provide more reliable gastric cancer risk information.

Risk factors for atrophic gastritis in the Japanese young and middle-aged: a study using double-contrast upper gastrointestinal barium X-ray radiography

PURPOSE

To identify risk factors for atrophic gastritis in Japanese young and middle-age subjects by double-contrast upper gastrointestinal barium X-ray radiography (UGI-XR).

MATERIALS AND METHODS

We included 351 consecutive Japanese subjects (158 males, 193 females; age 25-49 years, mean 44 years) seen between October 2014 and March 2016. All underwent serum Helicobacter pylori (Hp) antibody- and UGI-XR examinations. Two radiologists independently recorded their UGI-XR findings of atrophic gastritis (AG). Interobserver agreement was assessed by calculating the kappa (κ) coefficient. Univariate and multivariate analyses were performed to investigate the association between AG and the subjects' gender, smoking habit, alcohol intake, body mass index, and Hp infection.

RESULTS

AG was diagnosed in 85 subjects (24%) on UGI-XR images; interobserver agreement was good (κ = 0.745). By univariate analysis, the male gender and a high serum Hp titer (IgG ≥ 10 U/ml) were significantly association with AG (p < 0.05). Multivariate analysis revealed that a high serum Hp titer was the only independent, significant factor (p < 0.05). The odds ratio for a high serum Hp titer was 128 (95% CI, 54.8-498.4).

CONCLUSION

Our UGI-XR study indicated that Hp infection was significantly associated with AG in Japanese young and middle-aged subjects.

Serological Evaluation of Gastric Cancer Risk Based on Pepsinogen and Helicobacter pylori Antibody: Relationship to Endoscopic Findings

BACKGROUNDS AND AIMS

The serological risk-prediction system combined the pepsinogen (PG) test, and anti-Helicobacter pylori antibody is available for evaluation of gastric cancer risk. In this system, chronic atrophic gastritis (CAG) or H. pylori infection is diagnosed. Subjects with H. pylori negative and PG test negative (group A) are supposed to be those who have never been infected with H. pylori and are at extremely low risk for gastric cancer. However, a certain proportion of patients with CAG has been identified as the extremely low-risk group (group A). Here we examined endoscopic atrophy and investigated its relationship with the ABC classification system.

METHODS

We examined 540 patients. All patients underwent an endoscopic examination for evaluating corpus atrophy. Fasting sera were collected and serum PGs and anti-H. pylori antibody (Hp-Ab) titer (E-plate Eiken) were evaluated.

RESULTS

Of the 540 patients, 306 were classified into group A. However, 136 of them showed signs of endoscopic atrophy (group A with CAG). Group A with CAG frequently comprised the elderly. A new titer cut-off (<3 U/mL) of the Hp-Ab improved the discrimination of group A with CAG by 8%.

CONCLUSION

The prevalence of group A with CAG patients is a critical problem, especially in elderly subjects.

Preliminary study of automatic gastric cancer risk classification from photofluorography

AIM

To perform automatic gastric cancer risk classification using photofluorography for realizing effective mass screening as a preliminary study.

METHODS

We used data for 2100 subjects including X-ray images, pepsinogen I and II levels, PGI/PGII ratio, Helicobacter pylori (H. pylori) antibody, H. pylori eradication history and interview sheets. We performed two-stage classification with our system. In the first stage, H. pylori infection status classification was performed, and H. pylori-infected subjects were automatically detected. In the second stage, we performed atrophic level classification to validate the effectiveness of our system.

RESULTS

Sensitivity, specificity and Youden index (YI) of H. pylori infection status classification were 0.884, 0.895 and 0.779, respectively, in the first stage. In the second stage, sensitivity, specificity and YI of atrophic level classification for H. pylori-infected subjects were 0.777, 0.824 and 0.601, respectively.

CONCLUSION

Although further improvements of the system are needed, experimental results indicated the effectiveness of machine learning techniques for estimation of gastric cancer risk.

Characteristics of gastric cancer in negative test of serum anti-Helicobacter pylori antibody and pepsinogen test: a multicenter study

BACKGROUND AND AIM

The serological risk prediction system combines the pepsinogen test and anti-Helicobacter pylori (H. pylori) antibody determination. In this system, chronic atrophic gastritis (CAG) is diagnosed using the pepsinogen test. Patients who are H. pylori negative and pepsinogen negative are classified into group A, are assumed to be H. pylori uninfected, and are at an extremely low risk for gastric cancer. However, gastric cancers are detected in this group. The aim of this study is to clarify the clinicopathological status of group A patients with gastric cancer.

METHODS

A total of 109 gastric cancer patients classified as group A were enrolled in a multicenter study. Group A patients were divided into two subgroups: group AN (H. pylori uninfected) and group AP (H. pylori infected). They were compared to 183 H. pylori-infected gastric cancer patients who were not in group A.

RESULTS

Of the 109 patients, only 7 were classified as group AN; the other 102 were classified as group AP. The clinicopathological features of group AP included older age, predominantly differentiated type cancer, endoscopically visualized CAG, and pepsinogen (PG) I/II ratio lower than that of group AN. In group AN, the depressed type was dominant, and the PG I/II ratio was higher than in those gastric cancer patients who were infected with H. pylori.

CONCLUSION

Patients in group AP had CAG, and their gastric cancers were similar to those of H. pylori-eradicated patients. Concerning the recent ABC classification system, advanced decision criteria should be proposed to decrease the false-negative evaluation of gastric cancer risk.

Association between Gastric Cancer Risk and Serum Helicobacter pylori Antibody Titers

Background/Aims

It is difficult to confirm the accurate cutoff value to diagnose Helicobacter pylori (Hp) infection using commercial serology kits. It is reported that there were many cases with present/past infection that even the serum Hp-IgG antibody (HpAb) titers were below the cutoff value (e.g., 10 U/mL for E-Plate®), suggesting that we might overlook many gastric cancer (GC). We investigated an association between gastric cancer risk and serum Helicobacter pylori antibody titers.

Methods

We conducted a primary screening between 2014 and 2015. We performed gastroendoscopy if HpAb titers were ≥3.0 U/mL (i.e., more than measurable limit, E-Plate). These patients were divided into two groups: HpAb = 3.0–9.9 U/mL (“negative-high” group) and HpAb ≥ 10 U/mL; cutoff value (“over-10 U/mL” group). Hp infection status was investigated, and the number of GC patients was counted.

Results

Among the 3321 subjects in the primary screening, 56.9% (1891/3321) showed HpAb titers ≥3.0 U/mL; 1314 patients underwent gastroendoscopy. Ten were GC. 421 patients were “negative-high” group; two were GC. After evaluating 381 patients for Hp infection, 22.6%/60.6% was with present/past infection among the “negative-high” group.

Conclusion

We also found a correlation between HpAb titers and Hp infection status. “Negative-high” group has a risk of GC.

Correlation Between Expression of the Cancer/Testis Antigen KK-LC-1 and Helicobacter pylori Infection in Gastric Cancer

BACKGROUND/AIM

Our previous study indicated that Kita-kyushu lung cancer antigen-1 (KK-LC-1) is a cancer/testis antigen (CTA) expressed in 82% of gastric cancer cases. Here, we investigated the relationship between KK-LC-1 expression and Helicobacter pylori infection in Japanese patients with gastric cancer.

PATIENTS AND METHODS

We examined CTA expression in 25 surgical gastric cancer specimens and anti-H. pylori IgGs in the serum of each patient.

RESULTS

KK-LC-1 was expressed in 80% of tumor samples, markedly higher than melanoma antigen gene (MAGE)-A1, MAGE-A3, MAGE-A4, synovial sarcoma, X breakpoint 4 (SSX4) and New York esophageal squamous cell carcinoma-1 (NY-ESO-1). Anti-H. pylori IgG titers from the KK-LC-1-positive patients were significantly higher (67.5±7.6) than those from KK-LC-1-negative patients (15.8±7.5, p<0.01) although there were no significant differences between patients positive and negative for MAGE-A1, -A3 and-A4, SSX4 and NY-ESO-1.

CONCLUSION

As far as we are aware, this is the first report of a correlation between a carcinogen and CTA expression in clinical samples. KK-LC-1 was frequently expressed in gastric cancer caused by H. pylori infection. The risk diagnosis for gastric cancer might be more accurate if KK-LC-1 expression status were also considered.

Association between Increased Gastric Juice Acidity and Sliding Hiatal Hernia Development in Humans

OBJECTIVES

Several clinical factors; overweight, male gender and increasing age, have been implicated as the etiology of hiatal hernia. Esophageal shortening due to acid perfusion in the lower esophagus has been suggested as the etiological mechanism. However, little is known about the correlation between gastric acidity and sliding hiatus hernia formation. This study examined whether increased gastric acid secretion is associated with an endoscopic diagnosis of hiatal hernia.

METHODS

A total of 286 consecutive asymptomatic patients (64 were diagnosed as having a hiatal hernia) who underwent upper gastrointestinal endoscopy were studied. Clinical findings including fasting gastric juice pH as an indicator of acid secretion, age, sex, body mass index, and Helicobacter pylori infection status determined by both Helicobacter pylori serology and pepsinogen status, were evaluated to identify predictors in subjects with hiatal hernia.

RESULTS

Male gender, obesity with a body mass index >25, and fasting gastric juice pH were significantly different between subjects with and without hiatal hernia. The cut-off point of fasting gastric juice pH determined by receiver operating curve analysis was 2.1. Multivariate regression analyses using these variables, and age, which is known to be associated with hiatal hernia, revealed that increased gastric acid secretion with fasting gastric juice pH <2.1 (OR = 2.60, 95% CI: 1.38-4.90) was independently associated with hiatal hernia. Moreover, previously reported risk factors including male gender (OR = 2.32, 95% CI: 1.23-4.35), body mass index >25 (OR = 3.49, 95% CI: 1.77-6.91) and age >65 years (OR = 1.86, 95% CI: 1.00-3.45), were also significantly associated with hiatal hernia.

CONCLUSIONS

This study suggests that increased gastric acid secretion independently induces the development of hiatal hernia in humans. These results are in accordance with the previously reported hypothesis that high gastric acid itself induces hiatal hernia development.