Endoscopic Diagnosis and Therapy for Epstein-Barr Virus-Associated Gastric Cancer.

Epstein-Barr-virus-associated gastric cancer (EBVaGC) represents almost 7% of all GC and is a distinct subtype of GC with extreme DNA hypermethylation. EBVaGC is a tumor-infiltrating lymphocyte-rich tumor with little lymph-node metastasis in its early stage and with a relatively favorable prognosis in its advanced stage. Using upper gastrointestinal endoscopy, we recognize EBVaGC as a mainly depressed type with SMT-like protrusion in the upper part of the stomach near the gastric mucosal atrophic border or remnant stomach. The EBVaGC recognition rate of 21.4% with the endoscopic motif is not high, and further progress in endoscopic diagnosis of EBVaGC is needed. As less invasive endoscopic therapy, the extension of the criteria of endoscopic submucosal dissection (ESD) for early EBVaGC with little lymph-node metastasis should be discussed. Endoscopic diagnosis of EBVaGC may be relevant for the selection of patients who could benefit from endoscopic treatment or chemotherapy.

Epstein-Barr virus detection in endoscopic submucosal dissection-proven early gastric cancer with mixed-type histology.

BACKGROUNDS: Early gastric cancer (EGC) with mixed-type histology is a significant risk factor for additional surgery after endoscopic submucosal dissection (ESD). On the other hand, Epstein-Barr virus-associated gastric cancer (EBVaGC) with mixed-type histology is a favorable risk factor with regard to lymph node metastasis. METHODS: We performed EBV detection in 13 ESD-proven lesions in 13 cases of early gastric cancer with mixed-type histology using EBV-encoded small RNA1 in situ hybridization (EBER1 ISH). RESULTS: EBVaGC was diagnosed in only one (7.7%) of the tested lesions. That EBVaGC patient underwent surgery and there was no residual lesion and no lymph metastasis. EBVaGC is not frequent in EGC with mixed-type histology. CONCLUSIONS: EBV testing of gastric biopsy specimens seems not to be useful to predict the mixed-type histology results of ESD. However, EBV testing for ESD specimens of EGC with mixed-type histology is expected to be useful for avoiding excessive additional surgery.

Cooperation between artificial intelligence and endoscopists for diagnosing invasion depth of early gastric cancer.

BACKGROUND AND STUDY AIMS: The diagnostic ability of endoscopists to determine invasion depth of early gastric cancer is not favorable. We designed an artificial intelligence (AI) classifier for differentiating intramucosal and submucosal gastric cancers and examined it to establish a diagnostic method based on cooperation between AI and endoscopists. PATIENTS AND METHODS: We prepared 500 training images using cases of mainly depressed-type early gastric cancer from 250 intramucosal cancers and 250 submucosal cancers. We also prepared 200 test images each of 100 cancers from another institution. We designed an AI classifier to differentiate between intramucosal and submucosal cancers by deep learning. We examined the performance of the AI classifier and the majority vote of the endoscopists as high confidence and low confidence diagnostic probability, respectively, and cooperatively combined them to establish a diagnostic method providing high accuracy. RESULTS: Internal evaluation of the training images showed that accuracy, sensitivity, specificity, and F1 measure by the AI classifier were 77%, 76%, 78%, and 0.768, and those of the majority vote of the endoscopists were 72.6%, 53.6%, 91.6%, and 0.662, respectively. A diagnostic method based on cooperation between AI and the endoscopists showed that the respective values were 78.0%, 76.0%, 80.0%, and 0.776 for the test images. The value of F1 measure was especially higher than those by AI or the endoscopists alone. CONCLUSIONS: Cooperation between AI and endoscopists improved the diagnostic ability to determine invasion depth of early gastric cancer.

Endoscopic and pathologic motifs for the clinical diagnosis of Epstein-Barr virus-associated gastric cancer.

Objectives: Based on the recent therapeutic trends for gastric cancer (GC), the clinical impact of the diagnosis of Epstein-Barr virus (EBV)-associated GC (EBVaGC) appears to be important. We retrospectively analyzed endoscopic and pathologic motifs of GC lesions to narrow the number of candidates for EBV testing. Methods: We performed EBV tests for 32 upper gastrointestinal lesions of 32 patients in the clinical setting. These tests were ordered by endoscopists or by pathologists without an endoscopist's order. EBV-encoded small RNA1 (EBER1) in situ hybridization was used for the EBV tests. The endoscopic motif for the EBV test was the location in the upper part of the stomach or remnant stomach, mainly the depressed type with a submucosal tumor-like protrusion of the lesion. The pathologic motif was carcinoma with lymphoid stroma (CLS) or CLS-like histology of the lesion. We retrospectively analyzed the results of EBV tests for the endoscopic and pathologic motifs. Results: The final pathological diagnoses of the 32 subjects were 26 GCs including CLS, gastric endocrine cell carcinoma, gastric hepatoid carcinoma, gastric T-cell lymphoma, gastritis of the remnant stomach, esophageal adenocarcinoma, and esophageal squamous cell carcinoma. When nontypical lesions were excluded, the EBER1-positive rate was 42.3% (11/26) in GCs. Of the 14 GC lesions ordered examined by endoscopists, three (21.4%) were EBVaGC. Eight of the 12 (66.7%) GCs ordered examined by pathologists were EBVaGC. Conclusions: The pathologic motif is expected to be useful and the endoscopic motif may be helpful for EBVaGC diagnosis.

Application of Biopsy Samples Used for Helicobacter pylori Urease Test to Predict Epstein-Barr Virus-Associated Cancer.

Persistent gastric mucosal damage caused by Helicobacter pylori infection is a major risk factor for gastric cancer (GC). The Epstein-Barr virus (EBV) is also associated with GC. Most patients with EBV-associated GC are infected with H. pylori in East Asia. However, very few reports have described where and when both H. pylori and EBV infect the gastric mucosa. To clarify this, old biopsy samples used for the rapid urease test (RUT) were applied to count EBV genomic DNA (gDNA) copies using DNA probe quantitative polymerase chain reaction. DNA extracted from the gastric biopsy samples of 58 patients with atrophic gastritis was used to analyze the correlation between the degree of atrophic gastritis and the copy number of EBV gDNA. EBV was detected in 44 cases (75.9%), with viral copy numbers ranging from 12.6 to 4754.6. A significant correlation was found between patients with more than 900 copies of EBV gDNA and those with a more severe grade of atrophic gastritis (p = 0.041). This study shows that EBV can be detected in RUT samples in a manner that reduces patient burden.

Estimation of salt intake from spot urine may assist the risk assessment of gastric cancer.

Daily salt intake can be estimated by measuring sodium and creatinine concentrations in spot urine. Excessive salt intake is risk factor for gastric cancer. We examined the correlation between estimated salt intake from spot urine and risk of gastric cancer. This study included gastric cancer patients who underwent treatment at our hospital and patients in whom esophagogastroduodenoscopy was performed but gastric cancer was not observed. The history of H. pylori infection was known in these patients. Spot urine was collected, and daily salt intake was estimated from urine sodium and urine creatinine. Mean estimated salt intake was significantly higher in 120 gastric cancer patients (9.18 g/day) than in 80 non-gastric cancer patients (8.22 g/day). Multivariate analysis revealed estimated salt intake and H. pylori infection to be independent risk factors for gastric cancer. Among H. pylori-infected patients, salt intake was significantly higher in gastric cancer patients (9.25 g/day) than in non-gastric cancer patients (8.01 g/day). In conclusion, salt intake estimated from spot urine was high in patients with gastric cancer, especially in H. pylori infected patients. Spot urine is a simple examination and it may be applied as a new risk assessment of gastric cancer.

Epstein-Barr Virus-associated Early Gastric Cancer Treated with Endoscopic Submucosal Dissection: A Possible Candidate for Extended Criteria of Endoscopic Submucosal Dissection.

A 73-year-old man visited our hospital for the treatment of an early gastric cancer (GC) lesion. We performed en bloc resection using endoscopic submucosal dissection (ESD) for his GC lesion. The present GC lesion was Epstein-Barr virus (EBV)-associated poorly differentiated-type adenocarcinoma invading into the submucosal layer. Recently, accumulating data has shown that the risk of lymph node metastasis from early EBV GC without local lymphovascular infiltration is low. The present patient has been in good health for over three years since ESD. Some cases of early EBV GC with invasion into the submucosal layer may be candidates for further extension of the ESD criteria.

Clinicopathologic Characteristics of Epstein-Barr Virus-Associated Gastric Cancer Over the Past Decade in Japan.

: Epstein-Barr virus (EBV) is a ubiquitous human herpes virus, but related with several types of malignancies. Among EBV-related malignancies, EBV-associated gastric carcinoma (EBVaGC) has the largest patient's number. We screened for EBV infection in 1067 GC lesions of 1132 patients who underwent surgical resection from 2007 to 2017 in Japan and examined clinicopathological features of EBVaGC. EBV infection was detected by in situ hybridization with EBV-encoded small RNA 1(EBER-1 ISH). EBV was infected in 80 GC lesions (7.1%). Mean age was significantly lower in patients with EBVaGC than with EBV-negative GC. EBVaGC was more frequent in men than in women. EBVaGC was found twice as frequent in the upper or middle stomach as in the lower stomach. Early EBVaGC was more frequent, and submucosally invaded cases were dominant. The presence of lymphatic vessel invasion was less in EBVaGC, but frequency of lymph node metastasis was similar. Carcinoma with lymphoid stroma (CLS) was found in 3.8% (43/1132) of all lesions with 60.5% of EBV positivity. The synchronous or metachronous multiple GC was frequent in EBVaGC. We clarified clinicopathologic characteristics of EBVaGC over the past decade in Japan. EBV infection should be examined in gastric cancer cases showing these characteristics.

Clinical Importance of Epstein⁻Barr Virus-Associated Gastric Cancer.

Epstein⁻Barr virus-associated gastric carcinoma (EBVaGC) is the most common malignancy caused by EBV infection. EBVaGC has definite histological characteristics similar to gastric carcinoma with lymphoid stroma. Clinically, EBVaGC has a significantly low frequency of lymph node metastasis compared with EBV-negative gastric cancer, resulting in a better prognosis. The Cancer Genome Atlas of gastric adenocarcinomas proposed a molecular classification divided into four molecular subtypes: (1) EBVaGC; (2) microsatellite instability; (3) chromosomal instability; and (4) genomically stable tumors. EBVaGC harbors a DNA methylation phenotype, PD-L1 and PD-L2 overexpression, and frequent alterations in the PIK3CA gene. We review clinical importance of EBVaGC and discuss novel therapeutic applications for EBVaGC.

Image quality of a novel light-emitting diode (LED)-illuminated colonoscope.

BACKGROUND AND STUDY AIMS: Light-emitting diodes (LEDs) are used widely for their high luminous efficiency and durability. We developed a novel prototype high definition endoscope with white LEDs and evaluated the image quality it produced against a commercial endoscope with conventional light source. PATIENTS AND METHODS: The specifications of both colonoscopes were identical, except for the LED light source at the tip of the prototype. We examined 20 patients with rectal or sigmoid colon lesions and the image quality was evaluated in 40 images (one image from the LED colonoscope and one from the conventional colonoscope for each lesion) by three endoscopists. We additionally evaluated the 17 videos recorded with the LED colonoscope that were available. Image quality, mucosal and vascular color, and luminous distribution and intensity were scored on a 5-point scale. RESULTS: The mean score for vascular color given by one evaluator was significantly higher using the LED colonoscope than using the conventional colonoscope. The mean scores for mucosal color and luminous intensity from another evaluator were significantly lower with the LED colonoscope than with the conventional colonoscope. There were no significant differences in the luminous distribution scores for any of the evaluators. The image quality of the videos was evaluated as being similar with both colonoscopes. CONCLUSIONS: Image quality from the LED and conventional colonoscopes were similar, although the luminous intensity of the LEDs is inferior to that of the conventional light source at the present time.

Chronological Endoscopic and Pathological Observations in Russell Body Duodenitis.

A 64-year-old man was found to have a nodule in his right lung. He also complained of nausea and abdominal pain during the clinical course. Esophagogastroduodenoscopy revealed a duodenal ulcer associated with severe stenosis and a suspicion of malignancy. However, three subsequent biopsies revealed no evidence of malignancy. The fourth biopsy showed scattered large eosinophilic cells with an eccentric nucleus, leading to a diagnosis of Russell body duodenitis (RBD). RBD is an extremely rare disease, and little is known about its etiology and clinical course. The pathogenesis of RBD is discussed based on our experience with this case.

Epstein-barr virus in gastric carcinoma.

The Epstein-Barr virus (EBV) is detected in about 10% of gastric carcinoma cases throughout the world. In EBV-associated gastric carcinoma, all tumor cells harbor the clonal EBV genome. Gastric carcinoma associated with EBV has distinct clinicopathological features, occurs predominately in men and in younger-aged individuals, and presents a generally diffuse histological type. Most cases of EBV-associated gastric carcinoma exhibit a histology rich in lymphocyte infiltration. The immunological reactiveness in the host may represent a relatively preferable prognosis in EBV-positive cases. This fact highlights the important role of EBV in the development of EBV-associated gastric carcinoma. We have clearly proved direct infection of human gastric epithelialcells by EBV. The infection was achieved by using a recombinant EBV. Promotion of growth by EBV infection was observed in the cells. Considerable data suggest that EBV may directly contribute to the development of EBV-associated GC. This tumor-promoting effect seems to involve multiple mechanisms, because EBV affects several host proteins and pathways that normally promote apoptosis and regulate cell proliferation.

Colonization of an acid resistant Kingella denitrificans in the stomach may contribute to gastric dysbiosis by Helicobacter pylori.

In the stomach of a gastric ulcer patient who had been administered an anti-acid, a gram-negative and urease-negative bacillus similar in size to Helicobacter pylori was infected together with H. pylori. According to biochemical test and 16S rRNA gene analysis, the urease-negative bacterium was identified as Kingella denitrificans, a human nasopharyngeal commensal. In contrast to the standard strain of K. denitrificans, the isolate showed catalase activity, did not produce acid from glucose, and exhibited acid tolerance. Acid tolerance of H. pylori was increased by cocultivation with the K. denitrificans isolate, but not with other isolates of K. denitrificans. Disruption of physiological and immunological niche by dysbiotic colonization of bacterium may provide pathological attributes to human stomach. Collectively, a careful administration of anti-acids to the elderly, especially those with atrophic gastritis, is necessary to avoid repression of the gastric barrier to bacteria.

Endoscopic Resection is Infeasible for Early Gastric Cancers with Undifferentiated Components.

BACKGROUND/AIMS: Aim of this study is to find subgroup of early gastric cancer with lymph node metastasis for which successive further surgical operation is needed after endoscopic resection. METHODOLOGY: A total of 559 lesions of early gastric cancer, which had undergone curative gastrectomy, were enrolled in this study. We retrospectively investigated 10 clinicopathological factors predictive of lymph node metastasis by univariate and multivariate analysis. We showed the frequency of lymph node metastasis of subgroups in combination of independent factors selected by multivariate analysis. RESULTS: Lymph node metastases were detected in 57 lesions (10.2%). Univariate analysis revealed that lesion size > 30 mm, undifferentiated components, sm massive invasion, lymphatic invasion and venous invasion were factors significantly correlated with lymph node metastasis. By multivariate analysis, risk factors for lymph node metastasis were lesion size > 30 mm, undifferentiated components, sm massive invasion, and lymphatic invasion, with odds ratios of 2.17, 2.30, 5.88 and 8.24, respectively. In lesions with undifferentiated components, LNM were found in all subgroups. CONCLUSIONS: When we treat early gastric cancers contained undifferentiated components, even if they are predominantly differentiated-type intramucosal lesions, an additional surgical procedure should be considered or careful follow-up is required.

In vitro bactericidal effects of near-ultraviolet light from light-emitting diodes on Helicobacter pylori.

We investigated whether near-ultraviolet light emitted from light-emitting diodes (LEDs) effects Helicobacter pylori viability and whether this new method can potentially apply to eradication therapy. Three H. pylori strains were used for near-ultraviolet (UV) LED irradiation experiments. Viability of isolates exposed to near-UV light was compared with controls by counting colony forming units. A time-dependent bactericidal effect of near-UV light was definitely observed. LED irradiation with near-UV light showed effective bactericidal activity against H. pylori strains. Eradication therapy with LED might provide a new avenue of treatment in patients refractory to eradication due to antibiotic resistance and/or adverse effects of antibiotics.

Effect of Helicobacter pylori cdrA on interleukin-8 secretions and nuclear factor kappa B activation.

AIM: To investigate genetic diversity of Helicobacter pylori (H. pylori) cell division-related gene A (cdrA) and its effect on the host response. METHODS: Inactivation of H. pylori cdrA, which is involved in cell division and morphological elongation, has a role in chronic persistent infections. Genetic property of H. pylori cdrA was evaluated using polymerase chain reaction and sequencing in 128 (77 American and 51 Japanese) clinical isolates obtained from 48 and 51 patients, respectively. Enzyme-linked immunosorbent assay was performed to measure interleukin-8 (IL-8) secretion with gastric biopsy specimens obtained from American patients colonized with cdrA-positive or -negative strains and AGS cells co-cultured with wild-type HPK5 (cdrA-positive) or its derivative HPKT510 (cdrA-disruptant). Furthermore, the cytotoxin-associated gene A (cagA) status (translocation and phosphorylation) and kinetics of transcription factors [nuclear factor-kappa B (NF-κB) and inhibition kappa B] were investigated in AGS cells co-cultured with HPK5, HPKT510 and its derivative HPK5CA (cagA-disruptant) by western blotting analysis with immunoprecipitation. RESULTS: Genetic diversity of the H. pylori cdrA gene demonstrated that the cdrA status segregated into two categories including four allele types, cdrA-positive (allele types;Iand II) and cdrA-negative (allele types; III and IV) categories, respectively. Almost all Japanese isolates were cdrA-positive (I: 7.8% and II: 90.2%), whereas 16.9% of American isolates were cdrA-positive (II) and 83.1% were cdrA-negative (III: 37.7% and IV: 45.5%), indicating extended diversity of cdrA in individual American isolates. Comparison of each isolate from different regions (antrum and corpus) in the stomach of 29 Americans revealed that cdrA status was identical in both isolates from different regions in 17 cases. However, 12 cases had a different cdrA allele and 6 of them exhibited a different cdrA category between two regions in the stomach. Furthermore, in 5 of the 6 cases possessing a different cdrA category, cdrA-negative isolate existed in the corpus, suggesting that cdrA-negative strain is more adaptable to colonization in the corpus. IL-8 secretions from AGS revealed that IL-8 levels induced by a cdrA-disrupted HPKT510 was significantly lower (P < 0.01) compared to wild-type HPK5: corresponding to 50%-60% of those of wild-type HPK5. These data coincided with in vivo data that an average value of IL-8 in biopsy specimens from cdrA-positive and cdrA-negative groups was 215.6 and 135.9 pg/mL, respectively. Western blotting analysis documented that HPKT510 had no effect on CagA translocation and phosphorylation, however, nuclear accumulation of NF-κB was lower by HPKT510 compared to HPK5. CONCLUSION: Colonization by a cdrA-negative or cdrA-dysfunctional strain resulted in decreased IL-8 production and repression of NF-κB, and hence, attenuate the host immunity leading to persistent infection.

A novel colonoscope with high color-rendering white light-emitting diodes.

BACKGROUND: Light-emitting diodes (LEDs) are being used for a variety of new uses because of their cost-effectiveness and durability. We therefore considered using white LEDs as a light source for GI endoscopes to simplify the endoscopic system. OBJECTIVE: To assess the feasibility and safety of an LED-illuminated colonoscope. DESIGN: Pilot study of the LED colonoscope in healthy human volunteers and patients with colorectal lesions. SETTING: Yamaguchi University Hospital, Ube, Japan. INTERVENTIONS: We performed a total colonoscopy for 2 healthy volunteers and a sigmoidoscopy for 15 patients with colorectal lesions by using both LED and conventional colonoscopes. We assessed the feasibility and safety of the LED colonoscope by using a 5-grade scale. The 30 images of 15 colorectal lesions obtained by using each endoscope were evaluated in a blind, randomized order by 2 endoscopists. MAIN OUTCOME MEASUREMENTS: The mean scores of the LED colonoscope for the operability, ease of manipulation, image quality, and safety. RESULTS: We manufactured a prototype LED colonoscope with white LEDs on its tip. The LED colonoscope did not require an external light source or light-guide fiber bundle. The operability and ease of manipulation of the LED colonoscope were evaluated as similar to those of the conventional colonoscope. The color of the colonic mucosa and the vascular pattern were clearly visualized in the volunteers. For the 15 colorectal lesions, the mean score for image quality was not significantly different between the colonoscopes. The study was performed safely without any incident. LIMITATIONS: Single-center, small number of patients. CONCLUSIONS: The use of an LED colonoscope is feasible, and LED illumination may simplify the endoscope system.

Ultraslim endoscopy with flexible spectral imaging color enhancement for upper gastrointestinal neoplasms.

AIM: To conduct a preliminary study on the effect of flexible spectral imaging color enhancement (FICE) used in combination with ultraslim endoscopy by focusing on the enhanced contrast between tumor and non-tumor lesions. METHODS: We examined 50 lesions of 40 patients with epithelial tumors of the upper gastrointestinal tract before endoscopic submucosal dissection using ultraslim endoscopy with conventional natural color imaging and with FICE imaging. We retrospectively investigated the effect of the use of FICE on endoscopic diagnosis in comparison with normal light. RESULTS: Visibility of the epithelial tumors of the upper gastrointestinal tract with FICE was superior to normal light in 54% of the observations and comparable to normal light in 46% of the observations. There was no lesion for which visibility with FICE was inferior to that with normal light. FICE visualized 69.6% of hyperemic lesions and 58.8% of discolored lesions better than conventional endoscopy with natural color imaging. FICE significantly improved the visibility of lesions with hyperemia or discoloration compared with normocolored lesions. CONCLUSION: This study suggests that the use of FICE would improve the ability of ultraslim endoscopy to detect epithelial tumors of the upper gastrointestinal tract.