Characterization of Helicobacter pylori-Naïve Early Gastric Cancers

Diffuse Cyclin D1 and SPINK1 Expression in Gastric Oxyntic Gland Neoplasms: Promising Diagnostic Markers Identified Using Spatial Transcriptome Analysis

Oxyntic gland neoplasms typically arise in Helicobacter pylori-naive stomachs and are composed predominantly of chief cells, with a smaller component of parietal cells. Their pathologic diagnosis can be challenging owing to minimal cellular atypia. Especially in biopsy specimens with a limited tumor volume or when pathologists have limited experience in diagnosing this neoplasm, distinguishing them from normal oxyntic glands can be difficult, and no reliable diagnostic markers are currently available. In this study, single-cell spatial transcriptome analysis successfully identified significant upregulation of CCND1 and SPINK1 in all 6 analyzed cases of oxyntic gland neoplasms compared with normal oxyntic glands. Immunohistochemical analysis confirmed this finding in 21 endoscopically resected cases of oxyntic gland neoplasms, demonstrating that cyclin D1 and serine peptidase inhibitor Kazal type 1 (SPINK1) were diffusely expressed in oxyntic gland neoplasms, whereas their expression was scarcely observed in normal oxyntic glands, with a few of them showing weak to moderate staining. Even in biopsy specimens, these 2 markers highlighted the tumor areas and clearly distinguished neoplastic from normal oxyntic glands. Nonneoplastic foveolar epithelia and mucous neck cells also showed positive staining for both cyclin D1 and SPINK1. In addition, a mild increase in cyclin D1 expression and patchy or mosaic expression of SPINK1 were observed in fundic gland polyps, H. pylori-associated gastritis, and pyloric gland adenomas, whereas a diffuse staining pattern was specific to oxyntic gland neoplasms. These observations suggest that cyclin D1 and SPINK1 are reliable markers in differentiating oxyntic gland neoplasms from nonneoplastic oxyntic glands and pyloric gland adenomas. Cyclin D1 is commonly used for immunostaining in many pathology departments, and owing to its higher sensitivity and specificity compared with SPINK1, it is considered the best diagnostic marker.

Spectrum of gastric neoplasms in Helicobacter pylori-naïve patients

Chronic Helicobacter pylori (Hp) infection is the largest etiological factor for gastric cancer, but in recent years the reports of Hp-naïve gastric neoplasms (HpNGNs) have increased as the Hp-infected population in Japan has been declining. The histopathologic spectrum of HpNGNs differs significantly from that of conventional Hp-infected gastric neoplasms. Molecularly, the former harbor considerably fewer genetic and epigenetic abnormalities, reflecting the absence of chronic inflammatory conditions in the gastric mucosa. The majority of HpNGNs fall within several specific histological entities; each arise from particular background mucosa. Most originate from the fundic gland mucosa and have a gastric immunophenotype, as seen in foveolar-type gastric adenoma (FGA), oxyntic gland adenoma (OGA)/gastric adenocarcinoma of fundic gland type (GA-FG), signet-ring cell carcinoma (SRCC), and sporadic fundic gland polyp with dysplasia (FGPD). In contrast, tumors arising from the pyloric or cardiac gland mucosa have a diverse immunophenotype, as seen in intestinal-type gastric dysplasia (IGD) and gastric cardiac carcinoma. FGA, FGPD, SRCC, and IGD are mostly found as small intramucosal lesions. OGA/GA-FG frequently progresses to invasive carcinoma, but only a few have lymph node metastases. Thus, these tumors are regarded as precancerous lesions by Western pathologists, while in Japan they tend to be diagnosed as carcinomas, even in cases of low-grade dysplasia. Gastric cardiac carcinomas, on the other hand, are often found as advanced carcinomas and harbor a high malignant biological potential. A new diagnostic framework for gastric neoplasms is required in the present era of Hp-naïve individuals in Japan.

Linked color imaging and upper gastrointestinal neoplasia

White light imaging (WLI) can sometimes miss early upper gastrointestinal (UGI) neoplasms, particularly minimal changes and flat lesions. Moreover, endoscopic diagnosis of UGI neoplasia is strongly influenced by the condition of the surrounding mucosa. Recently, image-enhanced endoscopy techniques have been developed and used in clinical practice; one of which is linked color imaging (LCI), which has an expanded color range for better recognition of slight differences in mucosal color and enables easy diagnosis and differentiation of noncancerous mucosa from carcinoma. LCI does not require magnified observation and can clearly visualize structures using an ultrathin scope; therefore, it is useful for screening and surveillance endoscopy. LCI is particularly useful for detecting gastric cancer after Helicobacter pylori eradication, which accounts for most gastric cancers currently discovered, and displays malignant areas in orange or orange-red surrounded by intestinal metaplasia in lavender. Data on the use of convolutional neural network and computer-aided diagnosis with LCI for UGI neoplasm detection are currently being collected. Further studies are needed to determine the clinical role of LCI and whether it can replace WLI.

A mathematical simulation model to determine the optimal endoscopic screening strategy for detection of H. pylori-naïve gastric neoplasms

BACKGROUND

The effectiveness of esophagogastroduodenoscopy (EGD) screening in cohorts with low Helicobacter pylori prevalence is unknown. This study aimed to develop an optimally efficient EGD screening strategy for detecting H. pylori-naïve gastric neoplasms (HpNGNs).

METHODS

EGD data of 12 institutions from 2016 to 2022 were retrospectively analyzed. Age-related HpNGN prevalence, tumor growth rate, missing rate, and detection threshold size were calculated from the databases. Subsequently, using clinical data, a novel mathematical model that simultaneously simulated demographic changes and HpNGN detection was developed. Screening strategies using different starting ages (40/45/50 years) and intervals (2/5/10 years) were also compared. The detection rates of all tumors occurring within the virtual cohort and number-needed-to-test (NNT) were measured as outcomes.

RESULTS

Data of 519,368 EGDs and 97 HpNGNs (34 pure signet ring cell carcinomas, 26 gastric adenocarcinomas of the fundic gland type, 30 foveolar gastric adenoma-Raspberry type, and seven undifferentiated-type cancer cases) were analyzed. A virtual cohort with a 70-year time horizon was used to simulate the occurrence, growth, and detection of 346,5836 people. Among the strategies with detection rate > 50%, the screening strategy with a 5-year interval starting at 45 years of age had the lowest NNT. Adopting this strategy, most HpNGNs were detected at < 20 mm in size, and the deep submucosal invasion rate was less than 30%.

CONCLUSIONS

A mathematical simulation model revealed that screening every 5 years starting at 45 years of age could efficiently assist in identifying HpNGNs at an early stage.

Prevalence of Gastric Epithelial Tumors in Helicobacter pylori-uninfected Individuals Undergoing a Medical Checkup

Objective This study investigated the prevalence of gastric epithelial tumor in Helicobacter pylori-uninfected subjects who underwent esophagogastroduodenoscopy (EGD) as part of an annual checkup. Methods A total of 20,540 EGD examinations of H. pylori-uninfected individuals (12,917 men, 7,623 women; mean age 51.5±9.2 years old) were performed between April 2016 and March 2023. The prevalence of gastric epithelial tumor discovery and the size and location of each lesion type were analyzed. Results According to 20,540 examinations, 61 gastric epithelial tumors were endoscopically and histologically diagnosed in 58 of the subjects, with a prevalence rate of 0.28%. These tumors included signet-ring carcinoma (n=10, 0.05%), gastric adenocarcinoma of fundic-gland type (n=10, 0.05%), intestinal-type well-differentiated adenocarcinoma (n=2, 0.01%), and raspberry-type gastric foveolar tumors (n=36, 0.18%). One subject had two intestinal-type well-differentiated adenocarcinomas, and two each had two raspberry-type gastric foveolar tumors. The mean sizes of the signet-ring carcinomas, gastric adenocarcinoma of fundic-gland type, intestinal-type well-differentiated adenocarcinomas, and raspberry-type gastric foveolar tumors were 6.4, 4.7, 5.0, and 3.4 mm, respectively. Each lesion was located at a specific site in the stomach characteristic of its type. Conclusion In the present H. pylori-uninfected subjects, the prevalence of gastric epithelial tumors found on an EGD examination was 0.28%. Endoscopic examination should be performed in H. pylori-uninfected individuals to detect such tumors in characteristic locations.

Gastric dysplastic lesions in Helicobacter pylori-naïve stomach: Foveolar-type adenoma and intestinal-type dysplasia

Reports of Helicobacter pylori (Hp)-naïve gastric neoplasm (HpNGN) cases have been rapidly increasing due to the recent increase in the Hp-naïve population in Japan. Most HpNGNs exhibit the gastric immunophenotype and a low malignant potential regardless of histological type. Especially, foveolar-type gastric adenoma (FGA) and intestinal-type gastric dysplasia (IGD) rarely progress to invasive carcinoma. FGA is a foveolar epithelial neoplasm that occurs in the fundic gland (oxyntic gland) mucosa and is classified as the flat type or raspberry type (FGA-RA). The flat type is a large, whitish flatly elevated lesion while FGA-RA is a small reddish polyp. Genomically, the flat type is characterized by APC and KRAS gene mutations and FGA-RA by a common single nucleotide variant in the KLF4 gene. This KLF4 single-nucleotide variant reportedly induces gastric foveolar epithelial tumorigenesis and activates both cell proliferation and apoptosis, leading to its slow-growing nature. IGD consists of an intestinalized epithelial dysplasia that develops in the pyloric gland mucosa, characterized as a superficial depressed lesion surrounded by raised mucosa showing a gastritis-like appearance. Immunohistochemically, it exhibits an intestinal or gastrointestinal phenotype and, frequently, p53 overexpression. Thus, IGD shows unique characteristics in HpNGNs and a potential multistep tumorigenic process.

Clinicopathological and endoscopic features of Helicobacter pylori infection-negative gastric cancer in Japan: a retrospective study

BACKGROUND/AIMS

Helicobacter pylori infection-negative gastric cancer (HPNGC) has not been systematically investigated in consecutive patients. Hence, this study aimed to investigate the clinicopathological and endoscopic features of HPNGC.

METHODS

This single-center retrospective study selected participants from patients with gastric cancer who were treated at the Fukuoka University Chikushi Hospital between January 2013 and December 2021. Only patients diagnosed with HPNGC were enrolled, and their clinicopathological and endoscopic features were analyzed in detail.

RESULTS

The prevalence of HPNGC in the present study was 2.6% (54/2112). The types of HPNGC observed in each gastric region were as follows: advanced gastric cancer was observed in the cardia; gastric adenocarcinoma of fundic-gland differentiation, gastric adenocarcinoma of foveolar-type presenting with whitish elevation and raspberry-like foveolar-type gastric adenocarcinoma, gastric adenocarcinoma arising in polyposis, and gastric adenocarcinoma with autoimmune gastritis were observed in the fundic gland region ranging from the gastric fornix to the gastric body; signet-ring cell carcinoma was observed in the gastric-pyloric transition region ranging from the lower gastric body to the gastric angle; and well-differentiated tubular adenocarcinoma with low-grade atypia was observed in the antrum.

CONCLUSIONS

This study revealed that tumors from each gastric region exhibited distinct macroscopic and histological types in HPNGC.

Impact of metabolic dysfunction-associated fatty liver disease on the incidence of Helicobacter pylori-negative gastric cancer

AIM

The incidence of Helicobacter pylori-negative gastric cancer (HPNGC) is increasing worldwide. Recently, metabolic dysfunction-associated fatty liver disease (MAFLD) has been reported to be associated with various cancers, but its association with HPNGC has not been reported. We aimed to identify important independent factors associated with HPNGC, including MAFLD.

METHODS

This multicenter observational cohort study enrolled patients with gastric cancer (n = 1078) and health checkup examinees (n = 17 408). We analyzed patients with HPNGC (n = 26) and healthy participants with no H. pylori infection or any abnormal findings on upper gastrointestinal endoscopy (n = 1130). A logistic regression model was used to identify independent factors associated with HPNGC. The priority of the factors associated with HPNGC was evaluated using a decision-tree algorithm and random forest analysis.

RESULTS

Among all patients with gastric cancer, 2.4% (26/1078) were diagnosed with HPNGC (mean age, 64 years; male/female, 13/13). In the logistic regression analysis, age, smoking, and MAFLD (odds ratio, 6.5359; 95% confidence interval, 2.5451-16.7841; p < 0.0001) were identified as independent factors associated with HPNGC. Metabolic dysfunction-associated fatty liver disease was also identified as the most important classifier for the presence of HPNGC in decision-tree analyses. Helicobacter pylori-negative gastric cancer was observed in 5.2% of patients with MAFLD and 0.8% of patients without MAFLD. In the random forest analysis of the HPNGC, MAFLD was identified as the distinguishing factor with the highest variable importance (0.32).

CONCLUSIONS

Metabolic dysfunction-associated fatty liver disease was the most influential independent factor associated with HPNGC. These findings suggest that fatty liver and metabolic dysfunction could be involved in the pathogenesis of HPNGC.

Verrucous gastritis-like lesion in intramucosal Helicobacter pylori-uninfected signet ring cell carcinoma with poorly differentiated adenocarcinoma

In Japan, accessible Helicobacter pylori (Hp) eradication therapy is associated with an increase in the prevalence of gastric cancers (GCs) in Hp uninfected stomachs. Signet ring cell carcinoma (SRCC) is the most common of these GCs. Intramucosal SRCC with poorly differentiated adenocarcinoma (PDA) occurring in Hp uninfected gastric mucosa is rare; furthermore, many Hp uninfected pure SRCCs exhibit discoloration and flat or slightly depressed lesions, and morphological elevation is relatively rare. We report a case of intramucosal SRCC with PDA with an elevated, verrucous gastritis-like lesion in a 57-year-old male patient. In the present case, the PDA area showed dense tumor cell growth and coexisting desmoplastic and fibrotic reactions. Histopathology and immunohistochemical staining identified extensive fibromuscular obliteration with smooth muscle bundles extending from the muscularis mucosa into the lamina propria. The patient underwent curative endoscopic submucosal dissection. The reporting and analysis of such rare cases may lead to a better understanding of the characteristics of advanced Hp uninfected GCs.

Helicobacter pylori Infection Status and Gastric Tumor Incidence According to the Year of Birth

Background/Aims

: The prevalence of Helicobacter pylori-naive status is increasing. Nonetheless, biennial gastroscopy is recommended for all Koreans aged 40 to 75 years. This study aimed to determine whether gastric cancer screening guidelines could be changed according to H. pylori infection status and year of birth.

Methods

: Koreans who underwent serum assays and gastroscopy for gastric cancer screening between 2010 and 2016 were included if screening tests were followed up for ≥3 times. H. pylori infection was confirmed when invasive tests or 13C-urea breath tests were positive. In the case of negative test findings, eradication history, serologically detected atrophy, and intestinal metaplasia/atrophy were checked for past infection. If all were absent, H. pylori-naive status was confirmed.

Results

: Two-thousand and two (256 H. pylori-naive, 743 past-infected, and 1,003 infected) Koreans underwent screening tests for 95.5±28.4 months. The mean year of birth in the naive group (1969±7) differed from those of the past-infected (1957±10, p<0.001) and infected (1958±10, p<0.001) groups. H. pylori-naive status was correlated with recent year of birth (r=0.368, p<0.001). No gastric tumors were observed among the naive participants (p=0.007), whereas 23 adenomas, 18 adenocarcinomas, and two neuroendocrine tumors were detected in 1.9% (14/743) of past-infected and 2.5% (25/1,003) of infected participants, including four infected participants with metachronous tumors.

Conclusions

: The prevalence of H. pylori-naive status is increasing in young Koreans, and gastric tumors are rare in this population. Hence, biennial gastroscopy could be waived after the confirmation of naive status.

Clinicopathologic differences of gastric neoplasms between Helicobacter pylori-infected and -naïve patients: a multicenter retrospective analysis

BACKGROUND

The incidence of gastric neoplasms in Helicobacter pylori (Hp)-naïve patients has recently increased due to a remarkable decrease in the Hp-infected population in Japan. We investigated the clinicopathologic differences between Hp-infected gastric neoplasms (HpIGNs) and Hp-naïve gastric neoplasms (HpNGNs) that have not been fully elucidated so far.

METHODS

This retrospective multicenter study investigated 966 consecutive patients with 1131 gastric dysplasia or cancers who underwent endoscopic or surgical treatment for the recent decade. Clinicopathologic features were compared between HpIGN and HpNGN cases.

RESULTS

One thousand and sixty-eight HpIGNs in 916 patients included 877 differentiated types and 191 undifferentiated types. Sixty-three HpNGNs in 50 patients included 57 differentiated types (35 foveolar types, 15 intestinal types, 6 fundic-gland types, and 1 other differentiated type) and 6 undifferentiated types. HpNGNs occurred in younger (59.5 vs. 71.8 years, p < 0.05) and female patients (40.0% vs. 26.5%, p < 0.05), were found more frequently in the proximal compartment (p < 0.05), and had smaller size (median 4.0 vs. 20.0 mm, p < 0.05). Histologically, HpNGNs and HpIGNs both primarily consisted of differentiated type (90.5% vs. 82.1%, p = 0.089) and HpNGNs showed lower prevalence of invasive cancer (11.1% vs. 37.6%, p < 0.05) and lymphovascular invasion (1.6% vs. 31.6%, p < 0.05). Nearly all HpNGNs (62/63, 98.4%) were diagnosed in early pathological stage, while 16.1% (172/1068) of HpIGNs were diagnosed in advanced stage (p < 0.05).

CONCLUSIONS

HpNGNs is recently on the increase but shows lower malignant nature regardless of histologic type than HpIGN. Endoscopic gastric cancer screening will be reviewed via cost effectiveness for Hp-naïve individuals in future.

Identification of gastric signet ring cell carcinoma based on endoscopic images using few-shot learning

BACKGROUND

Deep learning (DL) models perform poorly when there are limited gastric signet ring cell carcinoma (SRCC) samples. Few-shot learning (FSL) can address the small sample problem.

METHODS

EfficientNetV2-S was first pretrained on ImageNet and then pretrained on esophageal endoscopic images (i.e., base classes: normal vs. early cancer vs. advanced cancer) using transfer learning. Second, images of gastric benign ulcers, adenocarcinoma and SRCC, i.e., novel classes (n = 50 per class), were included. Image features were extracted as vectors using the dual pretrained EfficientNetV2-S. Finally, a k-nearest neighbor classifier was used to identify SRCC. The above proposed 3-way 3-shot FSL framework was conducted in three rounds.

RESULTS

Dual pretrained FSL performed better than single pretrained FSL, endoscopists and traditional EfficientNetV2-S models. Dual pretrained FSL obtained the highest accuracy (79.4%), sensitivity (68.8%), recall (68.8%), precision (69.3%) and F1-score (0.691), and the senior endoscopist achieved the highest specificity of 93.6% when identifying SRCC. The macro-AUC and F1-score for dual pretraining (0.763 and 0.703, respectively) were higher than those for single pretraining (0.656 and 0.537, respectively), along with endoscopists and traditional EfficientNetV2-S models. The 2-way 3-shot FSL also performed better.

CONCLUSION

The proposed FSL framework showed practical performance in the differentiation of SRCC on endoscopic images, suggesting the potential of FSL in the computer-aided diagnosis for rare diseases.

Gastric Flat Elevated Undifferentiated Signet-ring Cell Mucosal Cancer Lesion Detected in a Case without Helicobacter pylori Infection

Protruded signet-ring cell carcinoma (SRCC) is extremely rare. We herein report a rare case of flat elevated gastric SRCC in a patient without Helicobacter pylori infection. Esophagogastroduodenoscopy of a woman in her 50s revealed a flat, whitish lesion in the gastric body with elevation. Histological results of an endoscopically biopsied specimen led to a diagnosis of SRCC. Resection using endoscopic submucosal dissection was performed, and histology results revealed that the tumor was localized in the lamina propria. The size was 10×6 mm, and a protrusion had been formed by SRCC enlargement without destruction of the surface epithelium structure.

Prevalence of Raspberry-type Gastric Foveolar-type Tumor in Individuals Undergoing Medical Checkups

Objective This study was performed to clarify the prevalence of raspberry-type gastric foveolar-type tumors, along with the time-course changes in the size and clinical course. Methods The subjects were 10,663 consecutive patients who underwent a medical checkup between April 2016 and March 2022, including an esophagogastroduodenoscopy (EGD) examination and determination of Helicobacter pylori infection status (uninfected, positive, post-eradication). The presence of characteristic reddish polypoid lesions in the stomach was investigated, and a diagnosis of raspberry-type gastric foveolar-type tumor was made based on histological findings. Results Thirty-eight cases had gastric polyps with a raspberry-like appearance on endoscopy, with 29 lesions in 28 cases endoscopically and histologically diagnosed as a raspberry-type gastric foveolar-type tumor. All of the affected subjects were determined to be H. pylori-uninfected. The prevalence of this type of lesion in all subjects was 0.26%, while that in the 6,635 H. pylori-uninfected subjects was 0.42%. An older age and the presence of a fundic gland polyp were found to be significant risk factors associated with the occurrence of the tumor. The mean size was 3.8±1.9 (range: 2-10) mm, and the location was in a fundic gland area in all affected subjects. Furthermore, examinations of previous EGD images revealed that two-thirds of the lesions had not changed in size, while follow-up EGD findings showed that lesions ≤5 mm in size had disappeared after a biopsy procedure. Conclusion The prevalence of raspberry-type gastric foveolar-type tumors was 0.42% in H. pylori-uninfected subjects. More than half of the lesions were too small to be removed by an endoscopic biopsy.

Endoscopic Diagnosis Strategy of Raspberry-Shaped Gastric Lesion in Helicobacter Pylori-Uninfected Patient

OBJECTIVES

We aimed to clarify the endoscopic and clinicopathological features of raspberry-shaped gastric lesions (RSGLs) and to establish an endoscopic diagnostic algorithm for RSGLs.

METHODS

We collected RSGLs from an endoscopic database at our hospital between May 2009 and August 2021. All RSGLs were histopathologically classified and compared based on their endoscopic and clinicopathological characteristics.

RESULTS

Sixty-five RSGLs in 54 patients were classified into five histopathological types: gastric adenocarcinoma of foveolar type (GA-FV, n = 43), gastric adenocarcinoma of fundic-gland type (GA-FG, n = 2), gastric adenocarcinoma of fundic-gland mucosa type (GA-FGM, n = 4), hyperplastic polyp (HP, n = 12), and proton pump inhibitor-related lesion (PPI-L, n = 4). All RSGLs exhibited polygonal or curved marginal crypt epithelium (MCE). GA-FV lesions had homogenously reddish (95%) and an irregular microvascular (MV) pattern (91%). GA-FG lesions were heterogeneously reddish with a submucosal tumor shape (100%) and had a regular MV pattern (50%). GA-FGM lesions were homogen+ously reddish (75%) and occasionally had a submucosal tumor shape (50%) with an irregular MV pattern (75%). HPs and PPI-Ls were homogeneously reddish (93%), with linear or dotted MCE (81%) and a regular MV pattern (100%).

CONCLUSION

Our diagnostic algorithm for RSGLs constructed using endoscopic features might be useful for the endoscopic differential diagnosis of RSGLs.

Gastric Foveolar-type Adenocarcinoma with Raspberry-like Appearance in a Helicobacter pylori-uninfected Stomach: A Long-term Retrospective Follow-up of 16 Years

Esophagogastroduodenoscopy in a 58-year-old man revealed a protruding lesion measuring 6 mm in diameter in the fornix. An endoscopic biopsy of the lesion indicated well-differentiated adenocarcinoma. The lesion was resected by polypectomy. According to the Japanese histologic diagnostic criteria, we made a final diagnosis of early gastric cancer (U, Gre, 6×6 mm, Type 0-I, tub1, pT1a (M), pUl0, Ly0, V0, pHM0, pVM0). A retrospective review of the endoscopic images showed that this lesion had already been present in the images taken 16 years ago. The size and morphology of the lesion were the same as those of the first detected lesion.

[Clinicopathological features of Helicobacter pylori-negative early gastric cancer]

OBJECTIVE

To investigate the clinicopathological features of Helicobacter pylori (Hp)-negative early gastric cancer.

METHODS

The clinicopathological data of 30 cases of Hp-negative early gastric cancer were collected retrospectively at Pingdingshan Medical District, 989 Hospital of PLA Joint Logistics Support Force, and Beijing Chaoyang Hospital, Capital Medical University, from 2009 to 2021, and the histomorphological characteristics and immunophenotype were observed, and combined with the literature to explore.

RESULTS

The median age of 30 patients was 58.5 years (range: 21-80 years), including 13 males and 17 females. The upper part of the stomach was 13 cases, the middle part of the sto-mach was 9 cases, and the lower part of the stomach was 8 cases. The median diameter of the tumor was 11 mm (range: 1-30 mm). According to the Paris classification, 9 cases were 0-Ⅱa, 7 cases were 0-Ⅱb, and 14 cases were 0-Ⅱc. Endoscopic examination showed that 18 cases of lesions were red, 12 cases of lesions were faded or white, and microvascular structures and microsurface structures were abnormal. In all the cases, collecting venules were regularly arranged in the gastric body and corner mucosa. There were 18 cases of well differentiated adenocarcinoma in the mucosa. The tumor presented glandular tubular-like and papillary structure, with dense glands and disordered arrangement; the cells were cuboidal or columnar, with increased nuclear chromatin and loss of nuclear polarity, and most of them expressed gastric mucin. Signet-ring cell carcinoma was found in 7 cases, all the cancer tissues were composed of signet-ring cells, and the cancer cells were mainly distributed in the middle layer to the surface layer of mucosa. Gastric oxyntic gland adenoma (gastric adenocarcinoma of the fundic gland type confined to mucosa) in 2 cases, gastric adenocarcinoma of the fundic gland type in 2 cases, and gastric adenocarcinoma of fundic gland mucosa type in 1 case. The tumor tissue was composed of branching tubular glands, except 1 case of mucosal surface epithelium was partially neoplastic, the other 4 cases of mucosal surface epi-thelium were all non-neoplastic; the cells were arranged in a single layer, and the nucleus was close to the basal side, and the nucleus was only slightly atypical. Pepsinogen I and H+/K+ ATPase were positive in 5 cases of gastric fundus gland type tumors, and 1 case of foveolar-type tumor cells at the surface and depth of mucosa showed MUC5AC positive. The gastric mucosa adjacent to cancer was generally normal in all cases, without atrophy, intestinal metaplasia and Hp.

CONCLUSION

Hp-negative early gastric cancer is a heterogeneous disease group with various histological types, and tubular adenocarcinoma and signet-ring cell carcinoma are common. Tubular adenocarcinoma mostly occurs in the elderly and the upper to middle part of the stomach, while signet-ring cell carcinoma mostly occurs in young and middle-aged people and the lower part of the stomach. Gastric neoplasm of the fundic gland type is relatively rare.

A Population-Based Helicobacter pylori Eradication Strategy Is More Cost-Effective than Endoscopic Screening

BACKGROUND

Helicobacter pylori (HP) eradication therapy is an efficient primary prevention method to reduce gastric cancer development. In Japan, biennial endoscopic screening for individuals aged 50 years and older is currently conducted as a national gastric cancer prevention program.

AIMS

We aimed to evaluate which strategy was the most optimal and cost-effective among HP eradication strategy, annual, biennial, and triennial endoscopic screening, and no screening as a national gastric cancer prevention program.

METHODS

We developed a state-transition model for HP eradication strategy, annual, biennial, and triennial endoscopic screening, and no screening using a healthcare payer perspective and a lifetime horizon. We targeted a hypothetical cohort of the Japanese population in their 20 s to 80 s. The main outcomes were costs, quality-adjusted life-years (QALYs), incremental cost-effectiveness ratios, gastric cancer cases, and deaths from gastric cancer. We performed one-way, two-way, and probabilistic sensitivity analyses.

RESULTS

HP eradication strategy was more cost-effective than endoscopic screening at any interval in all age groups. Cost-effectiveness was sensitive to HP infection rate. Cost-effective acceptability curves by Monte Carlo simulations for 10,000 trials demonstrated that HP eradication strategy was 100% cost-effective at a willingness-to-pay threshold of US$50,000 per QALY gained in all age groups. Over a lifetime, HP eradication strategy saves US$28.07 billion, increases 37.16 million QALYs, prevents 4.47 million gastric cancer cases, and saves 319,870 lives from gastric cancer.

CONCLUSION

A population-based HP eradication strategy is optimal and cost-effective for a national gastric cancer prevention program in Japan, replacing the current secondary prevention-focused biennial endoscopic screening.

Endoscopic and pathohistologic features of early gastric signet ring cell carcinoma presented as elevated type: A case report

Background

Almost all early gastric signet ring cell carcinomas (SRCCs) are the flat or depressed type, and the elevated type is rare. Here, we report the endoscopic and pathohistologic features of a rare case of SRCCs presented as the elevated type.

Case presentation

A 54-year-old man underwent esophagogastroduodenoscopy in our hospital because of intermittent upper abdominal pain for 6 years. White light endoscopy revealed an elevated lesion that is smooth and reddish and covered with normal mucosa and looked like a polyp. Magnifying endoscopy with narrow-band imaging showed broadened intervening parts, an elongated pit, and a dense microvascular network with focal irregularity. The lesion was considered as early gastric cancer and completely resected with endoscopic submucosal dissection. Pathohistological examination confirmed that the lesion was pure early SRCC that was limited within the mucosal lamina propria (T1a).

Conclusion

Elevated pure gastric SRCC is rare. This is a report of early pure gastric SRCC presented as the elevated type and the description of its endoscopic and pathohistologic features, which will contribute to the early detection of gastric SRCC.

Clinicopathological and molecular characterization of early gastric adenocarcinoma in Helicobacter pylori-uninfected patients: emphasis on differentiated gastric adenocarcinoma

BACKGROUND

Recently, Helicobacter pylori (HP)-uninfected gastric mucosal cancer has been reported; however, the clinicopathological and molecular features of HP-uninfected gastric cancer have not been elucidated.

METHODS

We evaluated the clinicopathological, immunohistochemical, and genetic alterations in HP-uninfected early gastric adenocarcinoma using next-generation sequencing (NGS).

RESULTS

Among 968 primary early gastric carcinomas, 64 (6.6%) were HP-uninfected gastric adenocarcinoma and were pathologically classified as gastric adenocarcinoma of fundic-gland type (GA-FG, n = 39), differentiated gastric adenocarcinoma (DGA, n = 16), and signet-ring cell carcinoma (SRCC, n = 9). Based on the expression profile of the mucin core protein, DGAs were classified into a gastrointestinal phenotype showing either MUC5AC or MUC6 expression and MUC2 or CD10 expression simultaneously (n = 5), and a gastric phenotype (n = 11) showing either MUC5AC or MUC6 expression. All DGAs with a gastrointestinal phenotype shared similar endoscopic characteristics, such as reddish depressed lesions in the antrum. In contrast, DGAs with a gastric phenotype exhibited several distinct endoscopic features, including a raspberry-shaped appearance and whitish flat-elevated appearance; the former expressed only MUC5AC and the latter exhibited co-expression of MUC5AC and MUC6. Among 16 HP-uninfected DGAs, seven were subjected to NGS. APC was recurrently mutated in DGA (42.9%) and was enriched in DGAs with a gastrointestinal phenotype (75%).

CONCLUSIONS

Overall, HP-uninfected gastric adenocarcinomas showed distinct clinicopathologic and endoscopic characteristics. Furthermore, HP-uninfected DGAs, especially those with a gastrointestinal phenotype, may be characterized by recurrent APC mutations.

Case report: New subtype of gastric adenocarcinoma arising from an H. pylori infection-negative stomach: Foveolar epithelium and mucous neck cell-mixed type adenocarcinoma

The characteristics of Helicobacter pylori (H. pylori) infection-negative gastric cancer have not been well documented because of its rarity, despite several types of H. pylori infection-negative gastric cancers being reported. In this report, we describe a case of early gastric cancer that developed without H. pylori infection with characteristic magnifying narrow-band imaging and novel histological findings. The difficulty in making an accurate diagnosis and differential diagnosis is highlighted, with the goal of providing more clinical experience for the diagnosis of H. pylori infection-negative gastric cancer.

Pathological Diversity of Gastric Cancer from the Viewpoint of Background Condition

BACKGROUND

The prevalence of Helicobacter pylori infection and chronic atrophic gastritis is decreasing in Japan, which has led to a decline in the incidence of gastric cancer. However, there are various subtypes of gastric cancer that arise from the background mucosa without H. pylori infection, and their histological characteristics are distinct from those of gastric cancer with chronic atrophic gastritis.

SUMMARY

In this review, after a brief overview of conventional gastric carcinoma with H. pylori infection, including its molecular classification, histological characteristics of gastric cancer after eradicating H. pylori are described. The clinicopathological characteristics of gastric cancer independent of H. pylori infection are then explained. Autoimmune gastritis (type A gastritis) increases the risk of gastric adenocarcinoma and neuroendocrine tumors. Gastric carcinoma without H. pylori infection has various histological subtypes, including fundic gland-type adenocarcinoma (oxyntic gland adenoma), foveolar-type adenocarcinoma/adenoma, signet ring cell carcinoma, and adenocarcinoma of the esophagogastric junction. In addition, some familial gastric cancer syndromes, including hereditary diffuse gastric cancer, familial adenomatous polyposis, and gastric adenocarcinoma and proximal polyposis of the stomach, are also discussed. Key Messages: Although the incidence of gastric cancer will decrease in the near future, the diversity of gastric cancer pathology will be enhanced because H. pylori-negative gastric cancer will have a significant impact on the clinical practice guidelines for gastric cancer. Gastroenterologists and pathologists should be aware of the morphological diversity of H. pylori-negative gastric cancer, and attention should be paid to the status of the background gastric mucosa while examining gastric cancer.

Effect of Helicobacter pylori infection on malignancy of undifferentiated-type gastric cancer

BACKGROUND

Although almost all cases of gastric cancer are caused by Helicobacter pylori (HP) infection, there are some rare exceptions. Furthermore, the clinicopathological characteristics of gastric cancer may differ depending on HP infection status. This study aimed to determine the clinicopathological characteristics of undifferentiated-type gastric cancer (UD-GC) according to HP status.

METHODS

The study involved 83 patients with UD-GC who were selected from 1559 patients with gastric cancer who underwent endoscopic resection at our hospital and whose HP infection status was confirmed. Clinicopathological characteristics were evaluated according to HP status (eradicated, n = 28; infected, n = 32; not infected, n = 23).

RESULTS

In patients without HP infection, UD-GCs were < 20 mm and intramucosal with no vascular invasion. In patients with eradicated HP, there was no correlation between development of UD-GC and time since eradication. Nine of twelve patients with a tumor detected ≥ 5 years after eradication had undergone yearly endoscopy. Submucosal invasion was observed in two of four patients and lymphovascular invasion in three of four patients whose UD-GC was detected ≥ 10 years after eradication. There was no significant between-group difference in the frequency of lesions with invasion into the submucosal layer or deeper (14.3%, 10.5%, and 0% in the UD-E, UD-I, and UD-U groups, respectively).

CONCLUSION

The clinicopathological characteristics of UD-GC were similar between HP-infected patients and HP-eradicated patients. Three of four patients with eradicated HP whose UD-GC developed ≥ 10 years after eradication were not eligible for endoscopic treatment and required additional surgery resection. In contrast, UD-GC was curable by endoscopic resection in all patients without HP infection.

A rare case of Helicobacter pylori–uninfected foveolar-type gastric cancer with submucosal invasion and lymph node metastasis

Gastric cancer without Helicobacter pylori infection accounts for less than 1% of all gastric cancers, and is generally considered to be less invasive. This report describes a rare case of H. pylori–uninfected gastric cancer with deep submucosal invasion and lymph node metastasis. Endoscopic submucosal dissection was performed, and pathological examination revealed tubular adenocarcinoma with deep submucosal invasion. We diagnosed foveolar-type gastric adenocarcinoma. While many cases of foveolar-type gastric adenocarcinoma, especially of the white elevated type, are reported as early stage gastric cancer, this case is very rare because it showed submucosal invasion and lymph node metastasis.

Intestinal-type gastric dysplasia in Helicobacter pylori-naïve patients

Gastric dysplasia and gastric cancer in Helicobacter pylori (Hp)-naïve patients usually exhibit a gastric phenotype, reflecting gastric mucosa without intestinal metaplasia (IM). We showed that intestinal-type gastric dysplasia (IGD) rarely occurs in the Hp-naïve stomach. In the last 10 years, we treated 1760 gastric dysplasia and gastric cancer patients, with 3.6% (63/1760) being Hp-naïve. Among these, ten were diagnosed with 14 IGDs and enrolled in this retrospective analysis. All lesions were observed by white-light endoscopy (WLE) and narrow-band imaging with magnification endoscopy (NBIME). We analyzed their endoscopic and microscopic features and patient demographics. Five men and five women aged 64 ± 21 years were included. WLE showed the depressed lesions mimicking a benign raised erosion in the prepyloric compartment. Multiple growths were confirmed in 30% (3/10) of patients. NBIME showed a near-regular microstructure and capillaries in 50% (7/14) of lesions with a gastritis-like appearance. Histologically, background mucosa was non-atrophic pyloric gland tissue, but 40.0% of samples (4/10) contained sporadic IM. Most of the lesions (8/14) were low-grade dysplasia, and others had a high-grade component, with one progressing to intramucosal carcinoma. The neoplastic surface was widely covered with foveolar epithelium in 57.1% (8/14). Immunohistochemically, neoplastic cells expressed CDX2 in all patients (14/14), MUC2 and CD10 in 92.9% (13/14), MUC5AC in 14% (2/14), and no expression of MUC6, showing an intestinal phenotype. Ki-67 was overexpressed with a mean labeling index of 58.3 ± 38.5%, and p-53 was overexpressed in 92.9% (13/14), regardless of the dysplastic grade. The IGD rarely occurs in Hp-naïve patients with distinctive clinicopathologic characteristics.

Economic and health impacts of introducing Helicobacter pylori eradication strategy into national gastric cancer policy in Japan: A cost-effectiveness analysis

BACKGROUND

Helicobacter pylori (H. pylori) eradication reduces gastric cancer risk. Since 2013, a population-wide H. pylori eradication strategy for patients with chronic gastritis has begun to prevent gastric cancer in Japan. The aim of this study was to evaluate the economic and health effects of H. pylori eradication strategy in national gastric cancer prevention program.

MATERIALS AND METHODS

We developed a cohort state-transition model for H. pylori eradication and no eradication over a lifetime horizon from a healthcare payer perspective, and performed one-way and probabilistic sensitivity analyses. We targeted a hypothetical cohort of H. pylori-positive patients aged 20, 30, 40, 50, 60, 70, and 80. The main outcomes were costs, quality-adjusted life-years (QALYs), life expectancy life-years (LYs), incremental cost-effectiveness ratios, gastric cancer cases, and deaths from gastric cancer.

RESULTS

H. pylori eradication was more effective and cost-saving for all age groups than no eradication. Sensitivity analyses showed strong robustness of the results. From 2013-2019 for 8.50 million patients, H. pylori eradication saved US$3.75 billion, increased 11.11 million QALYs and 0.45 million LYs, and prevented 284,188 cases and 65,060 deaths. For 35.59 million patients without eradication, H. pylori eradication has the potential to save US$14.82 billion, increase 43.10 million QALYs and 1.66 million LYs, and prevent 1,084,532 cases and 250,256 deaths.

CONCLUSIONS

National policy using population-wide H. pylori eradication to prevent gastric cancer has significant cost savings and health impacts for young-, middle-, and old-aged individuals in Japan. The findings strongly support the promotion of H. pylori eradication strategy for all age groups in high-incidence countries.

Sporadic foveolar-type gastric adenoma with a raspberry-like appearance in Helicobacter pylori-naïve patients

Sporadic foveolar-type gastric adenoma (FGA) has been described as an extremely rare polyp that is whitish and flatly elevated. However, we recently found that sporadic FGA with a raspberry-like appearance (FGA-RA) is not rare in Helicobacter pylori (H. pylori)-naïve gastric mucosa. We endoscopically or surgically treated 647 patients with gastric epithelial neoplasms in the last 5 years, with 7.7% (50/647) being H. pylori-naïve. Among these, 43 FGA-RAs were diagnosed based on histologic and endoscopic features in 34 patients, who were all enrolled in this retrospective study. All lesions were observed by white-light endoscopy (WLE) and narrow-band imaging with magnification endoscopy (NBIME). We subsequently analyzed their endoscopic and microscopic features and patient characteristics. The patients were 22 males and 12 females aged 57±23 years (mean±2SD). WLE showed raspberry-like small polyps mimicking gastric hyperplastic polyps in the oxyntic gastric compartment (body/fundus). Multiple growths were confirmed in 20.6% (7/34) of the patients. NBIME revealed irregularly shaped papillary/gyrus-like microstructures with abnormal capillaries. Histologically, all lesions were intraepithelial neoplasms, and most of lesions (62.8%, 27/43) exhibited low-grade dysplasia. Immunohistochemically, neoplastic cells featured strong and diffuse MUC5AC expression, negative or very low MUC6 expression, and negative MUC2/CD10 expression. They also showed Ki-67 hyperexpression with a mean labeling index of 59.4±48.7%. The coexistence of fundic gland polyps in the background mucosa was significantly higher in multiple FGA-RA cases than in solitary cases (100% vs. 55.5%, P< 0.05). FGA-RA is a newly suggested histologic variant of sporadic FGA whose occurrence is not rare in daily endoscopic practice.

Endoscopic and histological features of Helicobacter pylori-negative differentiated gastric adenocarcinoma arising in the antrum

BACKGROUND AND AIM

With the increasing prevalence of persons without Helicobacter pylori (HP) infection, cases of HP-negative gastric cancer are increasing. Although rare, cases of differentiated adenocarcinoma of the antrum have been reported in HP-negative patients. We collected cases with such lesions and investigated their endoscopic and histological features.

METHODS

Of 1965 consecutive patients with early gastric cancer who underwent endoscopic resection between January 2009 and December 2017, we extracted 9 cases of HP-negative differentiated adenocarcinoma located in the antrum (HPN-DAA). The clinical data, endoscopic findings, and histopathological findings were reviewed.

RESULTS

Of the nine patients with HPN-DAA, seven were male, and the median age was 53.8 years. The tumor arose from the pyloric gland mucosa in all cases. According to the endoscopic findings, the lesions were flat-elevated or depressed, mimicking varioliform gastritis. Magnifying endoscopy with narrow-band imaging showed the absence of a clear demarcation line or an irregular microvessel/surface pattern. As for the histopathological findings, eight of the nine lesions were diagnosed as high-grade dysplasia/intraepithelial neoplasia, while the remaining case was diagnosed as tubular adenocarcinoma with submucosal infiltration. The findings of immunohistochemistry confirmed that three cases were of the intestinal mucin phenotype and six were of the mixed gastric and intestinal mucin phenotype.

CONCLUSION

HPN-DAA is a very rarely occurring cancer that had never been recognized earlier. They belong to the new category of HP-negative cancers, and there seems to be a certain number of such cases.

Helicobacter pylori-negative Gastric Cancer

<i>Helicobacter pylori (H. pylori)</i>-negative gastric cancer is diagnosed when gastric malignancies are found in patients in <i>H. pylori</i>-naïve stomachs. There are four types of noncardiac <i>H. pylori</i>-negative gastric cancers. The signet ring cell-type poorly cohesive carcinoma is most common, followed by the chief cell-predominant type gastric adenocarcinoma of the fundic gland. Extremely well-differentiated adenocarcinoma of the corpus and well-differentiated pyloric gland cancers are rare outside Japan because of country-specific differences in diagnostic criteria. In endemic areas of <i>H. pylori</i> infection, strict criteria are required for diagnosing an <i>H. pylori</i>-naïve stomach. Both invasive and noninvasive <i>H. pylori</i> tests should show negative results in a subject without a history of <i>H. pylori</i> infection. Furthermore, the serum pepsinogen (PG) assay and endoscopic findings of the background gastric mucosa are required to discriminate subjects with past infections owing to spontaneous regression or unintended eradication of <i>H. pylori</i>. There should be no gastric corpus atrophy (PG I ≤70 ng/mL and PG I/II ≤3.0). Gastroscopy should reveal a regular arrangement of collecting venules without gastric xanthoma, metaplastic gastritis, or advanced atrophy over the angle. On biopsy, there should be no gastric atrophy, intestinal metaplasia, neutrophils, or <i>H. pylori</i> infiltration, and only a mild degree of mononuclear cell infiltration is permitted. The types and characteristics of noncardiac <i>H. pylori</i>-negative gastric cancers are summarized in this review, along with current diagnostic challenges found in Korea.

Clinicopathological and Endoscopic Features of Raspberry-Shaped Gastric Cancer in Helicobacter pylori-Uninfected Patients

BACKGROUND

Gastric adenocarcinoma of foveolar type (GA-FV) is a raspberry-shaped gastric cancer (RSGC) and garners much attention as H. pylori (Hp)-uninfected gastric cancer. However, the classification and clinicopathological and endoscopic features of RSGCs in Hp-uninfected patients are poorly defined. We designed a new histopathological classification of RSGC and compared them via endoscopic and clinicopathological characteristics.

SUMMARY

From 996 patients with early gastric cancers resected by endoscopy in our hospital, we studied 24 RSGC lesions from 21 (2.4%) Hp-uninfected patients. RSGCs were classified into 3 histological types as follows: GA-FV (n = 19), gastric adenocarcinoma of fundic gland type (GA-FG, n = 2), and gastric adenocarcinoma of fundic gland mucosa type (GA-FGM, n = 3). Most of the lesions were found at the greater curvature of the upper or middle third of the stomach. GA-FV lesions were homogeneously reddish and frequently accompanied with a whitish area around the tumor and an irregular microvascular (MV) pattern; these features were confirmed histopathologically by the presence of homogeneous neoplastic foveolar epithelium with foveolar hyperplasia around the tumors. GA-FG lesions might be heterogeneously reddish with a submucosal tumor shape and regular MV pattern; these were confirmed by the presence of covered or mixed nonneoplastic epithelium on deeper regions of tumors. GA-FGM lesions might be homogeneously reddish and occasionally had a submucosal tumor shape and irregular MV pattern; these were confirmed by the presence of homogeneous neoplastic foveolar epithelium on deeper regions of the tumors. Key Messages: RSGCs in Hp-uninfected patients are classified into 3 histopathological types. For accurate diagnosis of RSGCs, it may be necessary to fully understand endoscopic features of these lesions based on these histological characteristics and to take a precise biopsy.

Histopathologic Change of a Case of Gastric Oxyntic Neoplasm (Gastric Adenocarcinoma of Fundic Gland Mucosa Type) Through 5 Years With Concurrent Other Oxyntic Gland Lesions

Some gastric epithelial neoplasms show predominant chief cell differentiation (oxyntic gland neoplasms), in which the entity of "gastric adenocarcinoma of fundic gland type" was firstly designated, whereas a possible more aggressive subgroup "gastric adenocarcinoma of fundic gland mucosa type" (GA-FGM) was subsequently proposed. However, the histopathologic progression mode of these neoplasms has not been sufficiently reported. In this article, we describe a case of GA-FGM in which we could observe its progression during 5 years. The tumor was removed by endoscopic submucosal dissection 5 years after the first biopsy, which had already shown a feature of oxyntic gland neoplasm. During the follow-up period, the endoscopy revealed little change in the tumor appearance. However, the histology of endoscopic submucosal dissection showed submucosal extension with its histological progression. Besides, other oxyntic gland neoplasms of the stomach were observed metachronously or synchronously, giving an implication about a common pathogenetic basis of these lesions.

Genetic variants in the regulation region of TLR4 reduce the gastric cancer susceptibility

Gastric cancer (GC) is one of the most common cancers diagnosed in China. It has been suggested that the genetic polymorphisms of Toll-like receptors (TLRs) might be in close relation to tumorigenesis and development of gastric cancer. In this study, we performed a case-control study to investigate the genetic polymorphisms of TLR3, 4, 5, 7 with the genetic susceptibility of gastric cancer. TLRs gene polymorphisms in 471 gastric cancer (GC) patients and 471 healthy controls were analyzed by polymerase chain reaction-restrictive fragment length polymorphism (PCR-RFLP) analysis or TaqMan assays. Odds ratio (OR) and its 95% confidence interval (95%CI) were used to evaluate the association of TLR4 variants with the GC risk via unconditional logistic regression. Our results suggested that variant genotypes of TLR4 rs7869402 (OR = 0.61, 95%CI = 0.40-0.92, P = 0.02) and TLR4 rs7873784 (OR = 0.17, 95%CI = 0.09-0.33, P < 0.01) gene polymorphisms reduced the risk of GC. Stratified analysis showed that rs7869402 T-containing genotype significantly decreased the susceptibility of GC among females (OR = 0.38, 95%CI = 0.16-0.91, P = 0.03), older subjects (OR = 0.48, 95%CI = 0.26-0.87, P = 0.02), non-smokers (OR = 0.41, 95%CI = 0.23-0.71, P < 0.01) and non-drinkers (OR = 0.58, 95%CI = 0.30-0.78, P < 0.01). In case of rs7873784 polymorphism, C-containing genotype reduced the risk of GC among males (OR = 0.08, 95%CI = 0.03-0.21, P < 0.01), but not among females (OR = 0.53, 95%CI = 0.22-1.27, P = 0.15). As to the other four SNPs (TLR3 rs5743303, TLR4 rs1927914, TLR5 rs1640816 and TLR7 rs3853839), no significant correlations were found to be related to the risk of gastric carcinoma. Our research demonstrated the significance of TLRs polymorphisms in decreasing the risk of GC.

A rare case of Helicobacter pylori-uninfected intramucosal poorly differentiated adenocarcinoma that occurred in the gastric fornix

We report a rare case of undifferentiated-type intramucosal gastric cancer that occurred in the fornix of the stomach without Helicobacter pylori infection, which consisted mainly of poorly differentiated adenocarcinoma. A 49-year-old man visited our hospital for a follow-up endoscopic examination of a small depressed lesion of the gastric fornix detected by surveillance esophagogastroduodenoscopy. On magnifying endoscopy with blue laser imaging, the depressed lesion (approximately 10 mm in diameter) was regarded as undifferentiated-type early gastric cancer that proved to be a poorly differentiated adenocarcinoma by histological examination of biopsied specimens. The cancerous lesion was successfully treated with endoscopic submucosal dissection and microscopically showed an intramucosal cancer that invaded the whole mucosal layer with predominant growth of a poorly differentiated adenocarcinoma component. The patient status was verified as Helicobacter pylori-naïve according to the strict diagnostic criteria, thereby confirming this case as an undifferentiated-type Helicobacter pylori-uninfected gastric cancer. Helicobacter pylori-uninfected intramucosal poorly differentiated adenocarcinoma occurring in the gastric fornix has not been previously reported.

The rare case of elevated signet ring cell gastric carcinoma with Helicobacter pylori-naïve mucosa

Patients with Helicobacter pylori-naive mucosa may develop a pale, depressed signet ring cell gastric carcinoma or elevated gastric phenotype carcinoma. Almost all signet ring cell carcinomas are of the flat or depressed type, and elevated lesions are rare. We experienced a case of elevated signet ring cell carcinoma with Helicobacter pylori-naïve mucosa. Although the lesion needed to be differentiated from nonepithelial tumor, we diagnosed early and treated with endoscopic submucosal dissection. We report our case along with the relevant literature review.

A case of gastric adenocarcinoma considered to originate from a sporadic fundic gland polyp in a Helicobacter pylori-uninfected stomach

We encountered a rare case of gastric adenocarcinoma considered to arise from a sporadic fundic gland polyp (FGP). A woman in her 70 s, who had been prescribed a proton pump inhibitor for 5 years, was referred to our institution for further investigation and treatment of a gastric lesion. White light endoscopy showed numerous isochromatic FGPs in the greater curvature of the gastric body and a 15-mm reddish polypoid lesion with uneven surface characteristics. Magnifying endoscopy with narrow band imaging revealed an irregular granular microsurface structure with irregular microvessels, which is suggestive of cancer. The absence of atrophic changes in the entire gastric mucosa was confirmed endoscopically and histologically, and multiple Helicobacter pylori (HP) tests were negative. An en bloc resection was performed by polypectomy. The specimen showed adenocarcinoma that was thought to arise from an FGP. The lesion consisted of cystically dilated fundic glands in the basal part and neoplastic cells with nuclear atypia and high nuclear-cytoplasmic ratio in the foveolar part; on the basis of these findings, noninvasive adenocarcinoma was diagnosed. Although both adenocarcinoma in an HP-uninfected stomach and epithelial high-grade dysplasia in a sporadic FGP are extremely rare, this possibility should be considered when performing esophagogastroduodenoscopy.

Clinicopathological features of early gastric cancers arising in Helicobacter pylori uninfected patients

BACKGROUND

Persistent Helicobacter pylori (H. pylori) infection causes chronic inflammation, atrophy of the gastric mucosa, and a high risk of developing gastric cancer. In recent years, awareness of eradication therapy has increased in Japan. As H. pylori infections decrease, the proportion of gastric cancers arising from H. pylori uninfected gastric mucosa will increase. The emergence of gastric cancer arising in H. pylori uninfected patients though rarely reported, is a concern to be addressed and needs elucidation of its clinicopathological features.

AIM

To evaluate the clinicopathological features of early gastric cancer in H. pylori-uninfected patients.

METHODS

A total of 2462 patients with 3375 instances of early gastric cancers that were treated by endoscopic submucosal dissection were enrolled in our study between May 2000 and September 2019. Of these, 30 lesions in 30 patients were diagnosed as H. pylori-uninfected gastric cancer (HpUIGC). We defined a patient as H. pylori-uninfected using the following three criteria: (1) The patient did not receive treatment for H. pylori, which was determined by investigating medical records and conducting patient interviews; (2) Lack of endoscopic atrophy; and (3) The patient was negative for H. pylori after being tested at least twice using various diagnostic methods, including serum anti-H. pylori-IgG antibody, urease breath test, rapid urease test, and microscopic examination.

RESULTS

The frequency of HpUIGC was 1.2% (30/2462) for the patients in our study. The study included 19 males and 11 females with a mean age of 59 years. The location of the stomach lesions was divided into three sections; upper third (U), middle third (M), lower third (L). Of the 30 lesions, 15 were U, 1 was M, and 14 were L. Morphologically, 17 lesions were protruded and flat elevated type (0-I, 0-IIa, 0-IIa + IIc), and 13 lesions were flat and depressed type (0-IIb, 0-IIc). The median tumor diameter was 8 mm (range 2-98 mm). Histological analysis revealed that 22 lesions (73.3%) were differentiated type.The HpUIGC lesions were classified into fundic gland type adenocarcinoma (7 cases), foveolar type well-differentiated adenocarcinoma (8 cases), intestinal phenotype adenocarcinoma (7 cases), and pure signet-ring cell carcinoma (8 cases). Among 30 HpUIGCs, 24 lesions (80%) were limited to the mucosa; wherein, the remaining 6 lesions showed submucosal invasion. One of the submucosal invasive lesions showed more than 500 μm invasion. The mucin phenotype analysis identified 7 HpUIGC with intestinal phenotype and 23 with gastric phenotype.

CONCLUSION

We elucidated the clinicopathological characteristics of HpUIGC, revealing recognition not only undifferentiated-type but also differentiated-type. In addition, intestinal phenotype tumors were also observed and could be an important tip.

Potential of Helicobacter pylori-uninfected signet ring cell carcinoma to invade the submucosal layer

BACKGROUND AND AIM

The typical histology of Helicobacter pylori-uninfected gastric cancer is signet ring cell carcinoma (SRCC) localized in the mucosal layer, but the potential of these SRCCs to invade the submucosal layer is unclear. This study aimed to investigate the clinicopathological characteristics of SRCC in H. pylori-uninfected patient and its prevalence in diffuse-type gastric cancer (DGC) within Japan.

METHODS

We enrolled consecutive pure DGC patients diagnosed with the disease either localized in the mucosal layer or with submucosal invasion. H. pylori infection was investigated, and the patients were divided into three groups according to histological types: pure SRCC, SRCC with poorly differentiated adenocarcinoma (PDA), and pure PDA.

RESULTS

Of the 345 pure DGC patients, 132 (38%), 127 (37%), and 86 (25%) had pure SRCC, SRCC with PDA, and pure PDA histologies, respectively. The prevalence of H. pylori infection and the SM ratio were significantly lower in the pure SRCC group than other groups (P < 0.01). Twenty-two (6.4%) patients, including two with submucosal invasion, were negative for H. pylori and had mucosal SRCC component in the cancer lesions. Of the 259 SRCC cases (pure SRCC or SRCC + PDA), H. pylori-uninfected cases had different clinicopathological characteristics compared with H. pylori-positive cases. Particularly, the ratio of patients with submucosal invasive SRCC was significantly lower in the H. pylori-uninfected gastric cancer group than in those with H. pylori infection.

CONCLUSION

Helicobacter pylori-uninfected gastric cancer is not rare among pure DGC patients in Japan. SRCC in patients without H. pylori infection is less likely to be invasive.

Gastric adenocarcinoma coexisting with a reddish semipedunculated polyp arising from Helicobacter pylori-negative normal gastric mucosa: a report of two cases

We experienced two cases of adenocarcinoma coexisting with a hyperplastic polyp arising from Helicobacter pylori-negative normal gastric mucosa. The first case was of a 59-year-old man. Esophagogastroduodenoscopy revealed a protruding lesion measuring 4 mm in diameter on the greater curvature of the middle gastric body. The second case was of a 47-year-old man. Esophagogastroduodenoscopy showed a protruding lesion measuring 5 mm located at the greater curvature of the upper gastric body. The absence of atrophic changes in the entire gastric mucosa was confirmed endoscopically in both cases. Multiple H. pylori tests were all negative. Endoscopically, these protruding lesions appeared as reddish, semipedunculated polyps. Hyperplastic polyps were suspected based on white light endoscopic findings. Magnified endoscopy with narrow band imaging could not predict the coexistence of cancer. However, histopathological examination of the resected specimen revealed focal cancer at the surface of the gastric hyperplastic polyps. Considering the possibility that cancer may be coexisting in polyps, when reddish polyps are detected in H. pylori-negative normal gastric mucosa, it is important to perform a biopsy, or a careful follow-up endoscopy.