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Activating antibody-dependent cellular cytotoxicity (ADCC) by targeting claudin-18 isoform 2 (CLDN18.2) using zolbetuximab, a monoclonal antibody against CLDN18.2, has been considered a promising novel therapeutic strategy for gastric cancer (GC). However, the impact of CLDN18.2 expression on natural killer (NK) cells and monocytes/macrophages-crucial effector cells of ADCC-in GC has not been fully investigated. In the present study, we assessed the impact of CLDN18.2 expression on clinical outcomes, molecular features, and the frequencies of tumor-infiltrating NK cells and macrophages, as well as peripheral blood NK cells and monocytes, in GC by analyzing our own GC cohorts. The expression of CLDN18.2 did not significantly impact clinical outcomes of GC patients, while it was significantly and positively associated with Epstein-Barr virus (EBV) status and PD-L1 expression. The frequencies of tumor-infiltrating NK cells and macrophages, as well as peripheral blood NK cells and monocytes, were comparable between CLDN18.2-positive and CLDN18.2-negative GCs. Importantly, both CLDN18.2 expression and the number of tumor-infiltrating NK cells were significantly higher in EBV-associated GC compared to other molecular subtypes. Our findings support the effectiveness of zolbetuximab in CLDN18.2-positive GC, and offer a novel insight into the treatment of this cancer type, highlighting its potential effectiveness for CLDN18.2-positive/EBV-associated GC., (© 2024. The Author(s).)

Trastuzumab deruxtecan (T-DXd) showed statistically significant clinical improvement in patients with human epidermal growth factor receptor 2-positive (HER2 + ) gastric cancer in the DESTINY-Gastric01 trial. Exploratory results from DESTINY-Gastric01 suggested a potential benefit in patients with HER2-low gastric cancer. Spatial and temporal heterogeneity in HER2 expression or gene alteration, an inherent characteristic of gastric cancer tumors, presents a challenge in identifying patients who may respond to T-DXd. Specific biomarkers related to therapeutic response have not been explored extensively. Exploratory analyses were conducted to assess baseline HER2-associated biomarkers in circulating tumor DNA and tissue samples, and to investigate mechanisms of resistance to T-DXd. Baseline HER2-associated biomarkers were correlated with objective response rate (ORR) in the primary cohort of patients with HER2 + gastric cancer. The primary cohort had 64% concordance between HER2 positivity and HER2 (ERBB2) plasma gene amplification. Other key driver gene amplifications, specifically MET, EGFR and FGFR2, in circulating tumor DNA were associated with numerically lower ORR. Among 12 patients with HER2 gain-of-function mutations, ORR was 58.3% (7 of 12). ORR was consistent regardless of timing of immunohistochemistry sample collection. Further investigations are required in larger studies., (© 2024. The Author(s).)

The glycans form a unique complex on the surface of cancer cells and play a pivotal role in tumor progression, impacting proliferation, invasion, and metastasis. TRA-1-60 is a glycan that was identified as a critical marker for the establishment of fully reprogrammed inducible pluripotent stem cells. Its expression has been detected in multiple cancer tissues, including embryonal carcinoma, prostate cancer, and pancreatic cancer, but the biological and pathological characterization of TRA-1-60-expressing tumor cells remains unclear within various types of malignancies. Here, we report the biological characteristics of TRA-1-60-expressing gastric cancer cells, especially those with its cell surface expression, and the therapeutic significance of targeting TRA-1-60. The cells with cell membrane expression of TRA-1-60 were mainly observed in the invasive area of patient gastric cancer tissues and correlated with advanced stages of the disease based on histopathological and clinicopathological analyses. In vitro analysis using a scirrhous gastric adenocarcinoma line, HSC-58, which highly expresses TRA-1-60 on its plasma membrane, revealed increased stress-resistant mechanisms, supported by the upregulation of glutathione synthetase and NCF-1 (p47phox) via lipid-ROS regulatory pathways, as detected by RNA-seq analysis followed by oxidative stress gene profiling. Our in vivo therapeutic study using the TRA-1-60-targeting antibody-drug conjugate, namely, Bstrongomab-conjugated monomethyl auristatin E, showed robust efficacy in a mouse model of peritoneal carcinomatosis induced by intraperitoneal xenograft of HSC-58, by markedly reducing massive tumor ascites. Thus, targeting the specific cell surface glycan, TRA-1-60, shows a significant therapeutic impact in advanced-stage gastric cancers., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

The mechanism of metachronous recurrence (MR) after performing endoscopic treatment for early gastric adenocarcinoma (GAC) and eradicating Helicobacter pylori (H. pylori) is unknown. To elucidate the mechanism and risk factors of MR, we analyzed gene expression at multiple locations of the gastric mucosa. We selected each five patients with MR and without MR (control), after early GAC treatment and eradication of H. pylori. Mucosal tissue was collected from four sites in the stomach of each patient as biopsy specimens for mRNA sequencing, gene set enrichment analysis, and microRNA (miRNA) sequencing. We also performed correlation analysis and target prediction on pathways. As a result, endoscopically, the MR group had more intestinal metaplasia and enlarged folds. A total of 384 mRNAs presented changes in expression and 31 gene sets were enriched in the MR group. Immune-related pathways were enriched in the entire stomach, and the IFN-α response had the highest enrichment score. Additionally, 32 miRNAs revealed changes in their expression. Correlation analysis and target prediction with genes in the gene set of IFN-α response revealed that 10 miRNA-mRNA pairs presented a significant correlation. Immune-related pathways with miRNAs in the gastric mucosa after H. pylori eradication may be a risk factor for MR., (© 2023. The Author(s).)

Background: HER2 signaling might be involved in the regulation of immune cell activation in the tumor microenvironment (TME) of gastric cancer (GC). However, the relationship between HER2 status and immune cell condition in the HER2-positive GC TME is not clearly understood., Methods: To investigate the effect of HER2 signaling on the activation of the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway, which contributes to immune cell activation in the GC TME, we evaluated the associations among the expressions of HER2, cGAS-STING, and the number of CD8 + tumor-infiltrating lymphocytes (TIL) by considering HER2 heterogeneity in HER2-positive GC tissues. We also examined the effect of HER2 signaling on the activation of STING signaling in vitro using human HER2-positive GC cell lines., Results: The expression of HER2 is highly heterogeneous in HER2-positive GC tissues, and we found that the number of CD8 + TIL in HER2 high areas was significantly lower than that in HER2 low areas in HER2-positive GC tissues. Intriguingly, the tumor cell-intrinsic expression of STING, but not cGAS, was also significantly lower in the HER2 high areas than the HER2 low areas in HER2-positive GC tissues. Moreover, in vitro experiments, we demonstrated that the blockade of HER2 signaling increased the expression of STING and its target genes, including IFNB1, CXCL9/10/11, and CCL5, in HER2-positive GC cell lines., Conclusions: Our results suggest that HER2 signaling might suppress immune cell activation in the GC TME by inhibiting STING signaling in tumor cells in HER2-positive GC., (© 2023. The Author(s) under exclusive licence to The International Gastric Cancer Association and The Japanese Gastric Cancer Association.)

Background and Aims: Gastric submucosal tumors (SMTs) are treated or monitored according to GI stromal tumor guidelines, but the adequacy of the guidelines has not been thoroughly examined. We investigated the long-term course of gastric SMTs to determine the validity of guideline-based follow-up methods and the factors contributing to their size increase., Methods: This study included gastric SMTs diagnosed as GI mesenchymal tumors (GIMTs) by using EUS and followed up with EUS. The percentage and speed of GIMT enlargement and factors associated with the enlargement were investigated by using the Cox proportional hazards model., Results: From January 1994 to May 2022, a total of 925 gastric SMTs were evaluated with EGD, and 231 SMTs were diagnosed as GIMTs. Of the 231 GIMTs, 145 were examined by EUS more than twice and were followed up for >6 months. The mean ± standard deviation follow-up period was 5.20 ± 4.04 years (range, 0.5-17.3 years), with 39 (26.9%) of 145 GIMTs increasing in size with a mean doubling time of 3.60 ± 3.37 years. A multivariate analysis of factors influencing tumor growth revealed that irregular extraluminal borders were an increasing factor (hazard ratio, 3.65; 95% confidence interval, 1.26-10.52), initial tumor size ≤9.5 mm (hazard ratio, .23; 95% confidence interval, 0.07-0.77) was a nonincreasing factor, and GIMTs with calcification (n = 13) did not increase in size., Conclusions: Tumor growth in gastric GIMTs <9.5 mm in diameter and/or with calcification is rare. Follow-up intervals for these lesions could be extended., (Copyright © 2023 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.)

Background: The PI3K/AKT signaling pathway is frequently activated in gastric cancer (GC); however, AKT inhibitors are not effective in unselected GC patients in clinical trials. Mutations in AT-rich interactive domain 1A (ARID1A), which are found in approximately 30% of GC patients, activate PI3K/AKT signaling, suggesting that targeting the ARID1A deficiency-activated PI3K/AKT pathway is a therapeutic candidate for ARID1A-deficient GC., Methods: The effect of AKT inhibitors was evaluated using cell viability and colony formation assays in ARID1A-deficient and ARID1A knockdown ARID1A-WT GC cells as well as in HER2-positive and HER2-negative GC. The Cancer Genome Atlas cBioPortal and Gene Expression Omnibus microarray databases were accessed to determine the extent of dependence of GC cell growth on the PI3K/AKT signaling pathway., Results: AKT inhibitors decreased the viability of ARID1A-deficient cells and the inhibitory effect was greater in ARID1A-deficient/HER2-negative GC cells. Bioinformatics data suggested that PI3K/AKT signaling plays a greater role in proliferation and survival in ARID1A-deficient/HER2-negative GC cells than in ARID1A-deficient/HER2-positive cells, supporting the higher therapeutic efficacy of AKT inhibitors., Conclusions: The effect of AKT inhibitors on cell proliferation and survival is affected by HER2 status, providing a rationale for exploring targeted therapy using AKT inhibitors in ARID1A-deficient/HER2-negative GC., (© 2023. The Author(s) under exclusive licence to The International Gastric Cancer Association and The Japanese Gastric Cancer Association.)

Background: Gastric cancer is one of the leading causes of cancer deaths, and gastrectomy with lymph node dissection is the mainstay of treatment. Despite clinician efforts and advances in surgical methods, the incidence of complications after gastrectomy remains 10%-20% including fatalities. To the best of our knowledge, this is the first report on utilization of a deep learning method to build a new artificial intelligence model that could help surgeons diagnose these complications., Methods: A neural network was constructed with a total of 4000 variables. Clinical, surgical, and pathological data of patients who underwent radical gastrectomy at our institute were collected to maintain a deep learning model. We optimized the parameters of the neural network to diagnose whether these patients would develop complications after gastrectomy or not., Results: Seventy percent of the data was used to optimize the neural network parameters, and the rest was used to validate the model. A model that maximized the receiver operating characteristics (ROC) area under the curve (AUC) for validation of the data was extracted. The ROC-AUC, sensitivity, and specificity of the model to diagnose all complications were 0.8 vs 0.7, 81% vs 50%, and 69% vs 75%, for the teaching and validation data, respectively., Conclusions: A predictive model for postoperative complications after radical gastrectomy was successfully constructed using the deep learning method. This model can help surgeons accurately predict the incidence of complications on postoperative day 3., (© 2022 Asia Endosurgery Task Force and Japan Society of Endoscopic Surgery and John Wiley & Sons Australia, Ltd.)

A patient experienced gastric fundic gland-type hyperplastic polyps, consisting of foveolar epithelium and parietal cells, complicated with chronic bleeding due to long-term treatment with vonoprazan. The patient had progressive anemia, probably caused by bleeding from the polyps. After switching from vonoprazan to a histamine-2 (H2) receptor antagonist, the polyps markedly shrank and the anemia improved. Vonoprazan can produce reversible hyperplastic polyps and anemia. In case of anemia in patients receiving long-term vonoprazan, it is important to consider drug cessation or change to an H2 blocker., (© 2022. Japanese Society of Gastroenterology.)

Background/aim: Establishment of powerful and easy-to-evaluate biomarkers that can predict immune checkpoint inhibitor sensitivity in patients with gastric cancer (GC) would be highly useful. The albumin-derived neutrophil-to-lymphocyte ratio (Alb-dNLR) score reportedly is an excellent measure of both immunity and nutritional status. However, the association between nivolumab treatment sensitivity and Alb-dNLR in GC has also not been adequately investigated. This multicenter retrospective study was designed to evaluate the association of Alb-dNLR with therapeutic sensitivity of nivolumab in GC patients., Patients and Methods: This was a retrospective multicenter study with patients from five sites. The data from 58 patients who received nivolumab for postoperative recurrent or unresectable advanced GC between October 2017 and December 2018 were analyzed. Blood tests had been performed before nivolumab administration. We analyzed the correlation between the Alb-dNLR score and clinicopathological factors, including best overall response., Results: Of the 58 patients, 21 (36.2%) comprised the disease control (DC) group and 37 (63.8%) comprised the progressive disease (PD) group. The nivolumab treatment responses were subjected to receiver operating characteristic analysis. The cutoff value was set to 2.90 g/dl for Alb and to 3.55 for dNLR. All eight patients in the high Alb-dNLR group had PD (p=0.0049). The low Alb-dNLR group had significantly better overall survival (p=0.0023) and progression-free survival rates (p<0.0001)., Conclusion: The Alb-dNLR score was a very simple and sensitive predictor of nivolumab therapeutic sensitivity and has very good biomarker properties., (Copyright © 2023, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Background/aim: To discover the positive therapeutic effects of nivolumab in patients with advanced gastric cancer (AGC), it is necessary to establish a useful biomarker to predict therapeutic efficacy. This multicenter retrospective study sought to evaluate the predictive impact of inflammation-based prognostic score (IBPS) on the therapeutic efficacy of nivolumab in patients with AGC., Patients and Methods: In this retrospective study, we evaluated 58 AGC patients treated with nivolumab from October 2017 to November 2018 at five institutes. Patients were categorized follows: progressive disease (PD) or disease control (DC). Blood chemistry tests were performed immediately before and after two courses of nivolumab; the correlation between best overall response and IBPS was investigated. Transition of each blood serum marker was also assessed., Results: Of 58 patients, 37 (63.8%) were in the PD group and 21 (36.2%) in the DC group. No positive correlation was noted between IBPS and therapeutic efficacy of nivolumab both immediately before and after two courses of nivolumab. However, the neutrophil-lymphocyte ratio (NLR) (p=0.045) and prognostic index (PI) (p=0.0042) before nivolumab and NLR (p=0.025), PI (p=0.0030) and Glasgow prognostic score (GPS) (p=0.043) after nivolumab were significantly correlated with treatment sensitivity. Furthermore, a decrease in PNI was an independent prognostic factor to predict nivolumab resistance on univariate analyses (p=0.0051)., Conclusion: Although no association between IBPS and therapeutic sensitivity was found, it is important to focus on the transition of PNI to predict therapeutic efficacy of nivolumab., (Copyright © 2023 International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Purpose: To investigate efficacy and safety of trastuzumab deruxtecan (T-DXd) in human epidermal growth factor receptor 2 (HER2)-low gastric or gastroesophageal junction (GEJ) adenocarcinoma., Methods: Patients with locally advanced or metastatic HER2-low (cohort 1, immunohistochemistry 2+/in situ hybridization-negative; cohort 2, immunohistochemistry 1+) gastric/GEJ adenocarcinoma treated with at least two prior regimens, including fluoropyrimidine and platinum, but anti-HER2 therapy naive, received T-DXd 6.4 mg/kg intravenously once every 3 weeks. The primary end point was confirmed objective response rate by independent central review., Results: Among 21 patients enrolled in cohort 1 and 24 enrolled in cohort 2, 19 and 21 patients, respectively, had central HER2 confirmation, received T-DXd, and had measurable tumors at baseline. The confirmed objective response rate was 26.3% (95% CI, 9.1 to 51.2) from five partial responses in cohort 1 and 9.5% (95% CI, 1.2 to 30.4) from two partial responses in cohort 2. Thirteen patients (68.4%) in cohort 1 and 12 (60.0%) in cohort 2 experienced reduced tumor size. The median overall survival was 7.8 months (95% CI, 4.7 to nonevaluable) in cohort 1 and 8.5 months (95% CI, 4.3 to 10.9) in cohort 2; the median progression-free survival was 4.4 months (95% CI, 2.7 to 7.1) and 2.8 months (95% CI, 1.5 to 4.3), respectively. The most common grade ≥ 3 treatment-emergent adverse events in cohorts 1 and 2 were anemia (30.0% and 29.2%), decreased neutrophil count (25.0% and 29.2%), and decreased appetite (20.0% and 20.8%). Drug-related interstitial lung disease/pneumonitis occurred in one patient in each cohort (grade 1 or 2). No drug-related deaths occurred., Conclusion: This study provides preliminary evidence that T-DXd has clinical activity in patients with heavily pretreated HER2-low gastric/GEJ adenocarcinoma.

Objectives: Covered self-expandable metal stent (cSEMS) for gastric outlet obstruction (GOO) has been developed to overcome tumor ingrowth but is prone to be associated with an increased risk of migration. Clinical impact of the novel large-bore cSEMS for malignant GOO remains unclear., Methods: A total of 117 patients undergoing endoscopic cSEMS placement for malignant GOO were enrolled in this multicenter retrospective study. Technical and clinical success, adverse events, recurrent GOO, and survival after stent placement were compared between 24 mm-cSEMS (n = 49) and 20 mm-cSEMS (n = 68)., Results: Patient characteristics were well-balanced and thus similar survival was observed between the two groups (136 days vs. 89 days, P = 0.60). Technical success rate of 100% and clinical success rate of 96% were achieved both in 24 mm-cSEMS and 20 mm-cSEMS, respectively. The median cumulative time to recurrent GOO was significantly longer in 24 mm-cSEMS than in 20 mm-cSEMS (380 days vs. 138 days, P = 0.01). The incidence of adverse events and recurrent GOO was comparable: 12% vs. 15% (P = 0.91), and 16% vs. 31% (P = 0.11); however, no stent migration was observed in 24 mm-cSEMS. In a subgroup analysis, the superiority of 24 mm-cSEMS to 20 mm-cSEMS was demonstrated in extrinsic cancers (380 days vs. 121 days, P = 0.01) but not in intrinsic cancers (151 days vs. not reached, P = 0.47)., Conclusions: The 24 mm-cSEMS may improve time to recurrent GOO with ensuring acceptable safety in patients with malignant GOO., (© 2022 Japan Gastroenterological Endoscopy Society.)

Purpose: We are attempting to develop a navigation system for safe and effective peripancreatic lymphadenectomy in gastric cancer surgery. As a preliminary study, we examined whether or not the peripancreatic dissection line could be learned by a machine learning model (MLM)., Methods: Among the 41 patients with gastric cancer who underwent radical gastrectomy between April 2019 and January 2020, we selected 6 in whom the pancreatic contour was relatively easy to trace. The pancreatic contour was annotated by a trainer surgeon in 1242 images captured from the video recordings. The MLM was trained using the annotated images from five of the six patients. The pancreatic contour was then segmented by the trained MLM using images from the remaining patient. The same procedure was repeated for all six combinations., Results: The median maximum intersection over union of each image was 0.708, which was higher than the threshold (0.5). However, the pancreatic contour was misidentified in parts where fatty tissue or thin vessels overlaid the pancreas in some cases., Conclusion: The contour of the pancreas could be traced relatively well using the trained MLM. Further investigations and training of the system are needed to develop a practical navigation system., (© 2022. The Author(s) under exclusive licence to Springer Nature Singapore Pte Ltd.)

Background: Identification of positive biomarkers for the effects of nivolumab on patients with advanced gastric cancer (AGC) is significant. The Gustave Roussy Immune Score (GRIm-s) is associated with therapeutic resistance of immune checkpoint inhibitors (ICIs) in other cancers. This multicenter, retrospective study was designed to analyze the association of GRIm-s with therapeutic sensitivity of nivolumab in patients with AGC., Methods: We reviewed 58 patients with AGC treated with nivolumab from October 2017 to November 2018 at five participating institutions. We performed blood tests before the start of nivolumab and after administration of two courses. We evaluated the correlation between the best overall response and GRIm-s. Additionally, we focused on the changes in GRIm-s before the start of nivolumab and after administration of two courses., Results: Of the 58 patients, 21 (36.2%) were classified into the disease control (DC) group and 37 (63.8%) into the progressive disease (PD) group. GRIm-s before nivolumab treatment did not correlate with the best therapeutic response (p = 0.086). However, GRIm-s after two courses of nivolumab showed that significantly more PD cases were in the high-risk group (p < 0.0001). After two courses of nivolumab, overall survival was significantly worse in the high-risk group (p < 0.0001). For progression-free survival, the high-risk group had a significantly worse prognosis both before (p = 0.04) and after two courses of nivolumab treatment (p < 0.0001)., Conclusions: GRIm-s after two courses of nivolumab and its changes compared to pretreatment values proved beneficial in predicting nivolumab sensitivity., (© 2022. Society of Surgical Oncology.)

We herein report a case of a patient with gastric cancer-associated microscopic polyangiitis (MPA) who was treated with combination glucocorticoids and rituximab (RTX) for remission induction and maintenance, and finally to discontinue glucocorticoids without recurrence of gastric cancer or MPA in a year. A 69-year-old man was suspected of having MPA because of fever, high C-reactive protein levels, neuritis, and a high titer of myeloperoxidase-anti-neutrophil cytoplasmic antibody (MPO-ANCA). Upper gastrointestinal endoscopy indicated early-stage gastric cancer, for which he underwent surgery preceded by immunosuppressive therapy for vasculitis. Histopathological images showed vasculitis in the vicinity of the cancerous tissue, suggesting an association between gastric cancer and vasculitis. Postoperatively, fever and inflammatory response improved, but MPO-ANCA increased further and the patient developed alveolar hemorrhage. He resulted in remission with high-dose glucocorticoids and RTX, and he received maintenance therapy with RTX without additional immunosuppressive agents. After 1 year of treatment, he was able to discontinue glucocorticoids without recurrence of gastric cancer or vasculitis. There is no established treatment for malignancy-associated vasculitis other than glucocorticoids. Although more cases need to be accumulated in the future, RTX is expected to be useful in malignancy-associated vasculitis., (© Japan College of Rheumatology 2021. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background and objectives : Adenocarcinoma of the esophagogastric junction (AEG) has a complicated surgical anatomy, due to which it sometimes induces excessive intraoperative blood loss that necessitates intraoperative blood transfusion (BTF). However, few reports have focused on the impact of BTF on the survival outcomes of patients with AEG. We aimed to evaluate the impact of BTF on AEG prognosis. Materials and Methods : We included 63 patients who underwent surgical resection for AEG at our hospital between January 2010 and September 2020. Clinicopathological characteristics and survival outcomes were compared between patients with ( n = 12) and without ( n = 51) BTF. Multivariate analysis was performed to identify the independent prognostic factors for overall survival. Results : None of the patients who underwent minimally invasive surgery received BTF. Patients who received BTF had a significantly worse 5-year survival rate than those who did not (67.8% vs. 28.3%, p = 0.001). BTF was an independent risk factor for overall survival (hazard ratio: 3.90, 95% confidence interval 1.30-11.7), even after patients who underwent minimally invasive surgery were excluded. Conclusions : BTF adversely affected the survival outcomes of patients with AEG who underwent curative surgery. To avoid BTF, surgeons should strive to minimize intraoperative bleeding.

Background: Although nivolumab (anti-programmed cell death-1 antibody) is a promising approach for advanced gastric cancer (AGC), the response rate remains limited. The aim of this multicenter retrospective study was to determine if clinical features could serve as prognostic factors of the efficacy of nivolumab in patients with AGC., Methods: Fifty-eight patients with AGC who were treated with nivolumab as a third or later line from October 2017 to December 2018 at any of five clinical sites were enrolled in the study. The correlation between the best overall response and clinical features was investigated. Overall survival and progression-free survival after initiation of nivolumab were calculated and clinical features that could be predictors of the prognosis were sought., Results: The disease control rate (DCR) for nivolumab was 36.2% and was significantly correlated with performance status (p = 0.021), metastasis to one organ (p = 0.006), and grade 2 or higher immune-related adverse events (p = 0.027). There was also a significant association between response to nivolumab and ability to receive subsequent chemotherapy (p = 0.022). In the analysis of overall survival, the following variables were identified as being significantly associated with a poor outcome: Eastern Cooperative Oncology Group performance status ≥1, prior treatment with trastuzumab, no immune-related adverse events, lack of a response to nivolumab, and inability to receive subsequent chemotherapy., Conclusion: The findings of this study suggest that nivolumab may be ineffective for AGC in patients with poor performance status and those with a history of treatment with trastuzumab., (© 2021. The Author(s).)

Background: Pulmonary tumor thrombotic microangiopathy (PTTM), a rare manifestation of metastatic cancer with poor prognosis, is characterized by subacute/acute fatal pulmonary hypertension. The main cause of PTTM is gastric cancer, and cases of early gastric cancer confirmed using autopsy have been reported. Moreover, several cases of early gastric cancer that are undetectable on endoscopy or macroscopic postmortem examination have been reported., Case Presentation: A previously healthy 50-year-old man presented with progressive dyspnea and cough for 1 month. Echocardiography suggested pulmonary hypertension. Computed tomography revealed diffuse lymphadenopathy, whereas blood work revealed an elevation in several serum tumor marker levels. Despite normal upper endoscopic findings, a presumptive diagnosis of PTTM due to gastric cancer was made based on pathological findings of cervical lymph node biopsy, which indicated signet ring cell carcinoma. Imatinib and tegafur/gimeracil/oteracil plus oxaliplatin therapy were started on day 7. The patient's condition was initially stable. However, his symptoms suddenly progressed, and the patient died on day 8. Macroscopic postmortem examination revealed no abnormal gastric wall findings. Microscopically, PTTM was confirmed, and multiple serial sections of the stomach revealed early gastric cancer., Conclusions: Despite normal endoscopic findings, micro-occult gastric cancer can lead to PTTM. Physicians should be aware of this disease presentation. Taking prompt action is needed when PTTM is suspected, even if the patient appears stable., (© 2021. The Author(s).)

Purpose: Systemic inflammatory responses play a key role in cancer progression, and detecting the predictive inflammatory response markers is needed. The present study explored inflammatory response markers capable of predicting survival in patients with gastric cancer., Methods: We enrolled 264 patients, who underwent curative gastrectomy for clinical stage (cStage) I-III gastric cancer between 2012 and 2015. The cut-off point of eight preoperative inflammatory response markers was determined by receiver operating characteristic (ROC) curve analysis. The marker with the highest Harrell's concordance index (C-index) was adopted for subsequent univariate and multivariate analyses using the Cox proportional-hazards model., Results: Among eight representative inflammatory response markers, lymphocyte-to-monocyte ratio (LMR; cut-off point, 4.60) achieved the highest C-index (0.633). The 5-year survival rate was significantly worse in patients with LMR < 4.60 than in those with LMR ≥ 4.60 (67.5% versus 89.0%, P < 0.001). In multivariate analysis, LMR < 4.60 was identified as an independent prognostic factor (hazard ratio: 2.372; 95% confidence interval: 1.266-4.442; P = 0.007)., Conclusion: In this study, LMR had the strongest ability to predict the survival of patients with gastric cancer among other inflammatory response markers, with lower LMRs being associated with poor survival following curative gastrectomy., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: A time interval between diagnosis and surgery for gastric cancer is necessary, although its impact on survival remains controversial. We evaluated the impact of preoperative time interval on survival in gastric cancer patients., Methods: We enrolled 332 patients who underwent curative gastrectomy for clinical stage (cStage) I-III gastric cancer between 2012 and 2015. We separately analyzed early- (cStage I) and advanced-stage (cStages II and III) patients. Early-stage patients were divided according to preoperative time interval: short (≤ 42 days) and long (> 42 days) groups. Advanced-stage patients were also divided into short (≤ 21 days) and long (> 21 days) groups. We compared the survival between the short and long groups in early- and advanced-stage patients., Results: The median preoperative time interval was 29 days, and no significant differences were found in patient characteristics between the short and long groups in early- and advanced-stage patients. In early-stage patients, the 5-year survival rates of the short and long groups were 86.5% and 88.4%, respectively (P = 0.917). In advanced-stage patients, the 5-year survival rates were 72.1% and 70.0%, respectively (P = 0.552). In multivariate analysis, a longer time interval was not selected as an independent prognostic factor in early- and advanced-stage patients., Conclusions: In this study, survival difference was not found based upon preoperative time interval. The results do not affirm the delay of treatment without reason, however, imperative extension of preoperative time interval may be justified from the standpoint of long-term survival., (© 2021. Société Internationale de Chirurgie.)

In 2020, Olympus Medical Systems Corporation introduced the Texture and Color Enhancement Imaging (TXI) as a new image-enhanced endoscopy. This study aimed to evaluate the visibility of neoplasms and mucosal atrophy in the upper gastrointestinal tract through TXI. We evaluated 72 and 60 images of 12 gastric neoplasms and 20 gastric atrophic/nonatrophic mucosa, respectively. The visibility of gastric mucosal atrophy and gastric neoplasm was assessed by six endoscopists using a previously reported visibility scale (1 = poor to 4 = excellent). Color differences between gastric mucosal atrophy and nonatrophic mucosa and between gastric neoplasm and adjacent areas were assessed using the International Commission on Illumination L*a*b* color space system. The visibility of mucosal atrophy and gastric neoplasm was significantly improved in TXI mode 1 compared with that in white-light imaging (WLI) (visibility score: 3.8 ± 0.5 vs. 2.8 ± 0.9, p < 0.01 for mucosal atrophy; visibility score: 2.8 ± 1.0 vs. 2.0 ± 0.9, p < 0.01 for gastric neoplasm). Regarding gastric atrophic and nonatrophic mucosae, TXI mode 1 had a significantly greater color difference than WLI (color differences: 14.2 ± 8.0 vs. 8.7 ± 4.2, respectively, p < 0.01). TXI may be a useful observation modality in the endoscopic screening of the upper gastrointestinal tract.

Background: Epstein-Barr virus (EBV)-positive gastric carcinoma (GC) is defined by the proliferation of GC cells with EBV infection. The co-existence of EBV-positive and -negative components in a single GC is rare. We report a case of GC with the co-existence of EBV-positive and EBV-negative components, in which we performed-for the first time-various molecular analyses to elucidate their histogenesis., Case Presentation: An 81-year-old man was diagnosed with GC based on the results of endoscopy and a pathological examination of the biopsy specimen. Systemic chemotherapy was performed, since lymph node and lung metastases were diagnosed based on computed tomography. Total gastrectomy and lymph node dissection were performed after chemotherapy, after confirming that the size of the metastatic lymph nodes had decreased and that the lung metastasis had disappeared. Grossly, a type 3 tumor was located in the middle posterior part of the stomach body. At the cut section, the tumor consisted of a white and solid part on the anal side of the tumor and a flat and elevated part on the oral side. Histologically, the former part consisted of GC with lymphoid stroma and the latter part was composed of poorly differentiated adenocarcinoma without prominent lymphocytic infiltration. The two histopathological components were clearly separated from each other. On EBV-encoded small RNA (EBER)-in situ hybridization (ISH), the part with the lymphoid stroma component was positive, while the other part was negative. Immunohistochemistry revealed that both components showed the overexpression of p53. Sequencing of TP53 using DNA extracted from the two components was conducted, and revealed different patterns. Targeted next generation sequencing revealed MYC amplification in the EBV-positive component of the tumor and HER2 amplification in the EBV-negative part. Immunohistochemistry revealed that the EBV-positive part was C-MYC( +)/HER2(-) and the EBV-negative part was C-MYC(-)/HER2( +). Correspondingly, chromogenic ISH and dual-color ISH showed amplification of C-MYC and no amplification of HER2 in the EBV-positive part, and no amplification of C-MYC and amplification of HER2 in the EBV-negative part., Conclusion: We presented a case of collision of two different GCs composed of EBER-ISH ( +)/C-MYC ( +) and EBER-ISH (-)/HER2 ( +) cells.

Background/aim: Laparoscopic gastrectomy (LG) is more frequently associated with postoperative liver enzyme elevation (PLEE) than open gastrectomy in phase III clinical trials for Japanese gastric cancer patients. The aim of this study was to determine the risk factors for PLEE after LG for gastric cancer., Patients and Methods: This study enrolled 153 consecutive patients with gastric cancer who underwent LG. The patient characteristics, the liver retraction method [silicone disc (SD) or Nathanson liver retractor (NLR)], and perioperative outcomes were compared between patients with and without PLEE., Results: PLEE was observed in 26 patients (17%). The patients with PLEE exhibited longer operative times (p=0.005) and more frequent use of the NLR for liver retraction (p=0.022). In the multivariate analysis, liver retraction using the NLR (p=0.003) and aberrant left hepatic artery (ALHA) ligation (p=0.042) were independent risk factors of PLEE., Conclusion: Liver retraction with the SD during LG was shown to be the safer method that is less likely to cause postoperative liver dysfunction. ALHA preservation may contribute to avoiding postoperative liver dysfunction., (Copyright© 2021, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

AT-rich interactive domain 1A (ARID1A), which is a tumor suppressor gene, is frequently mutated in Epstein-Barr virus-positive gastric cancer [EBV (+) GC]. While most ARID1A mutations in GC are truncating mutations, leading to loss of ARID1A protein expression, epigenetic modifications appear to contribute to ARID1A deficiency in EBV (+) GC harboring wild-type ARID1A. Based on the significant role of epigenetic modifications in EBV (+) GC that contributes to ARID1A deficiency, the methylation status of ARID1A was evaluated in EBV-infected cells and GC patients using a publicly available microarray and the Cancer Genome Atlas (TCGA) database. EBV-encoded miRNAs that potentially target ARID1A were identified as an additional epigenetic modulator by computational prediction. In vitro experiments were conducted to evaluate how EBV-encoded miRNAs affected ARID1A mRNA and protein levels. In clinical GC samples, the expression of predicted miRNAs and ARID1A and the mutation status of ARID1A was evaluated. As results, ARID1A was not hypermethylated in EBV (+) GC samples or EBV-infected GC cells. EBV infection did not alter ARID1A mRNA levels, suggesting that ARID1A protein deficiency was caused by post-transcriptional gene silencing in ARID1A-WT EBV (+) GC. Overexpression of miR-BART11-3p and miR-BART12, which were identified as miRNAs that potentially bind ARID1A, suppressed ARID1A protein expression in MKN7 and NCI-N87 cells. Highly expressed miR-BART11-3p and miR-BART12 were correlated with decreased ARID1A levels in GC tumors which did not harbor ARID1A mutations. The present findings revealed that ARID1A expression was epigenetically regulated by miR-BART11-3p and miR-BART12 in EBV (+) GC., (© The Author(s) 2020. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Epstein-Barr virus-positive gastric cancer [EBV (+) GC] is a distinct GC subtype with unique genetic and epigenetic aberrations. Here, we examined resected GC samples and publicly available microarray data and The Cancer Genome Atlas (TCGA) database to identify the mechanism underlying overexpression of PD-L1 in EBV (+) GC. We found that high levels of PD-L1 overexpression in EBV (+) GC were caused by focal amplification of CD274. By contrast, relatively high expression of PD-L1 in tumor tissue and infiltrating immune cells correlated with CD8 lymphocyte infiltration and IFN-γ expression via IRF3 activation. Since we reported previously that PD-L1 expression is associated both with the presence of CD8 T cells in the tumor microenvironment and with IFN-γ expression in GC, we examined a database to see whether IFN-γ-associated overexpression of PD-L1 plays a significant role in EBV (+) GC. Immunohistochemical staining showed that expression of the IRF3 signature in clinical GC samples was higher in EBV (+) than in EBV (-) cases. The data presented herein reveal a unique dual mechanism underlying PD-L1 overexpression in EBV (+) GC: high focal amplification of CD274 or IFN-γ-mediated signaling via activation of IRF3.

Background: AT-rich interactive domain 1A (ARID1A) is a tumor suppressor gene that is frequently mutated in gastric cancer (GC). Although ARID1A mutations are not a druggable target for conventional treatments, novel therapeutic strategies based on a synthetic lethal approach are effective for ARID1A-deficient cancers. The histone methyltransferase EZH2 acts in a synthetic lethal manner in ARID1A-mutated ovarian cancer, although its role in GC remains unknown., Methods: The selective sensitivity of the EZH2 inhibitors for ARID1A-deficient GC cells was evaluated using cell viability and colony formation assays. The expression of PI3K/AKT signaling genes were investigated using TCGA's cBioPortal database to determine whether the homeostasis between ARID1A and EZH2 is related to cell proliferation and survival via the PI3K/AKT signaling pathway. We also evaluated the phosphorylation of PI3K/AKT signaling proteins in ARID1A knock downed ARID1A-WT GC cells., Results: EZH2 inhibitors decreased the viability of ARID1A-deficient cells in a dose-dependent manner and demonstrated the selective sensitivity to ARID1A-deficient cells in vitro experiment system. Bioinformatics approach revealed that the PI3K/AKT signaling was tended to be activated in ARID1A-deficient GC enhancing cell viability and, furthermore, down-regulation of EZH2 in ARID1A-deficient GC was related to normalization of PI3K/AKT signaling pathway. The cell experiment revealed that phosphorylated AKT was upregulated in ARID1A-deficent GC cells., Conclusions: The present findings provide a rationale for the selective sensitivity of EZH2 inhibitors against ARID1A-deficient GC and suggest the potential efficacy of targeted therapy using EZH2 inhibitors in this patient population.

Background: Gastric cancer (GC) patients with PD-L1-negative tumor occasionally have a favorable response to anti-PD-1 mAb. The aim of the present study was to investigate the regulatory mechanism and immunosuppressive role of PD-L2 in GC., Methods: We used immunohistochemistry to evaluate the expression of PD-L2 in primary tumors from 194 patients with GC. The mechanism of PD-L2 expression was assessed in TCGA stomach adenocarcinoma tissue dataset and in vitro assay using GC cell lines. The immunosuppressive role of PD-L2 was evaluated by cytotoxicity of CTL clone against PD-L2 expressing GC cells., Results: PD-L2 was expressed on tumor cells (TCs) of 28.4% patients and PD-L2 expression on TCs was significantly associated with tumor progression. TCGA dataset revealed that IFN-γ and, to a lesser extent, IL-4 signature significantly correlated with PD-L2 expression. In vitro assay showed that IFN-γ and, also to a lesser extent, IL-4 can upregulate PD-L2 expression on GC cells. Anti-PD-L2 mAb significantly enhanced the cytotoxicity of CTL clone against GC cell lines expressing PD-L2., Conclusions: PD-L2 is expressed on GC cells and PD-1/PD-L2 interaction are functionally involved in anti-tumor CTL activities. PD-L2 expression should be considered when determining the optimal immunotherapy for GC.

Background: Trastuzumab deruxtecan (DS-8201) is an antibody-drug conjugate consisting of an anti-HER2 (human epidermal growth factor receptor 2) antibody, a cleavable tetrapeptide-based linker, and a cytotoxic topoisomerase I inhibitor. The drug may have efficacy in patients with HER2-positive advanced gastric cancer., Methods: In an open-label, randomized, phase 2 trial, we evaluated trastuzumab deruxtecan as compared with chemotherapy in patients with HER2-positive advanced gastric cancer. Patients with centrally confirmed HER2-positive gastric or gastroesophageal junction adenocarcinoma that had progressed while they were receiving at least two previous therapies, including trastuzumab, were randomly assigned in a 2:1 ratio to receive trastuzumab deruxtecan (6.4 mg per kilogram of body weight every 3 weeks) or physician's choice of chemotherapy. The primary end point was the objective response, according to independent central review. Secondary end points included overall survival, response duration, progression-free survival, confirmed response (response persisting ≥4 weeks), and safety., Results: Of 187 treated patients, 125 received trastuzumab deruxtecan and 62 chemotherapy (55 received irinotecan and 7 paclitaxel). An objective response was reported in 51% of the patients in the trastuzumab deruxtecan group, as compared with 14% of those in the physician's choice group (P<0.001). Overall survival was longer with trastuzumab deruxtecan than with chemotherapy (median, 12.5 vs. 8.4 months; hazard ratio for death, 0.59; 95% confidence interval, 0.39 to 0.88; P = 0.01, which crossed the prespecified O'Brien-Fleming boundary [0.0202 on the basis of number of deaths]). The most common adverse events of grade 3 or higher were a decreased neutrophil count (in 51% of the trastuzumab deruxtecan group and 24% of the physician's choice group), anemia (38% and 23%, respectively), and decreased white-cell count (21% and 11%). A total of 12 patients had trastuzumab deruxtecan-related interstitial lung disease or pneumonitis (grade 1 or 2 in 9 patients and grade 3 or 4 in 3), as adjudicated by an independent committee. One drug-related death (due to pneumonia) was noted in the trastuzumab deruxtecan group; no drug-related deaths occurred in the physician's choice group., Conclusions: Therapy with trastuzumab deruxtecan led to significant improvements in response and overall survival, as compared with standard therapies, among patients with HER2-positive gastric cancer. Myelosuppression and interstitial lung disease were the notable toxic effects. (Funded by Daiichi Sankyo; DESTINY-Gastric01 ClinicalTrials.gov number, NCT03329690.)., (Copyright © 2020 Massachusetts Medical Society.)

Objective: Long-term administration of proton pump inhibitors (PPIs) after eradication of Helicobacter pylori infection has been reported to increase the risk for development of gastric cancer (GC). We investigated whether long-term administration of PPI affects ectopic and metachronous recurrence of GC after endoscopic treatment. Methods: Participants were 687 patients who underwent endoscopic treatment for GC from January 2005 to March 2018. Questionnaire surveys and medical record reviews of medications, including PPIs, H 2 receptor antagonists and low-dose aspirin (LDA) were conducted for all patients. The influence of PPI in ectopic and metachronous recurrence of GC was evaluated with Cox's proportional hazard analysis. Results: Patients who did not respond to the questionnaire and those who underwent additional treatment after endoscopic treatment were excluded from analyses; 418 patients were included. During an average observation period of 1608 days (range, 375-4993 days), 136 patients (32.5%) took PPIs for more than 1 year and 94 took PPIs for more than 3 years; of those, 40 had ectopic and metachronous recurrences. Cox's proportional hazards analysis revealed that long-term use of PPIs (for both 1 year and 3 years) was not a risk factor for recurrence. In addition, age, severity of gastric atrophy, long-term use of LDA, current infection with H. pylori , and cure achieved with the first endoscopic treatment were also not risk factors for recurrence. Conclusions: Long-term use of PPIs does not affect ectopic and metachronous recurrence of GC after endoscopic treatment.

Introduction: Endoscopic submucosal dissection (ESD) for early gastric cancer (EGC) is well accepted. However, its adaptation for elderly patients is unclear. This study aimed to investigate the prognosis and long-term outcomes of ESD for EGC in elderly patients aged ≥80 years by comparing their findings to the findings of patients aged <80 years., Materials and Methods: The study included 533 patients (632 lesions). The patients were divided into an elderly group (age, ≥80 years; 108 patients; 128 lesions; mean age, 83.4 ± 2.7 years) and a nonelderly group (age, <80 years; 425 patients; 504 lesions; mean age, 69.6 ± 7.9 years). We compared patient and lesion characteristics, overall survival (OS), and disease-specific survival (DSS) between the 2 groups retrospectively. Multivariate analysis was performed to clarify the risk factors of death after ESD., Results: The rate of curative resection and adverse events was not significantly different between the groups. The mean survival time periods with regard to OS/DSS in the elderly and nonelderly groups were 75.8 ± 5.9 and 122.8 ± 2.6 months ( P < 0.05)/120.0 ± 3.0 and 136.4 ± 0.6 months (not significant), respectively. In the elderly group, eGFR <30 ml/min/1.73 m 2 was an independent risk factor of death (hazard ratio = 5.32; 95% confidence interval = 1.39-20.5; P =0.015)., Conclusion: ESD for EGC can be performed safely and can achieve high curability with good prognosis in elderly patients aged ≥80 years. After ESD, close attention should be paid to elderly patients with severe chronic kidney disease., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2019 Kenichiro Okimoto et al.)

Background: Trastuzumab deruxtecan (DS-8201a) is a novel HER2-targeted antibody-drug conjugate with a humanised anti-HER2 antibody, cleavable peptide-based linker, and topoisomerase I inhibitor payload. A phase 1, non-randomised, open-label, multiple-dose study was done to assess the safety, tolerability, and activity of trastuzumab deruxtecan in HER2-expressing advanced solid tumours. The dose escalation (part 1) has previously been reported and the recommended doses for expansion of 5·4 mg/kg or 6·4 mg/kg were established. In this Article, we report the safety and preliminary activity results from this phase 1 trial in all patients with HER2-positive gastric or gastro-oesophageal junction cancer who received trastuzumab deruxtecan at the recommended doses for expansion., Methods: This was an open-label, dose-escalation and dose-expansion phase 1 trial done at eight hospitals and clinics in the USA and six in Japan. Eligible patients were at least 18 years old in the USA and at least 20 years old in Japan and had advanced solid tumours (regardless of HER2 expression in dose escalation or HER2 expression or mutation in dose expansion). The recommended doses for expansion of 5·4 mg/kg or 6·4 mg/kg trastuzumab deruxtecan were administered intravenously to patients once every 3 weeks until withdrawal of consent, unacceptable toxicity, or progressive disease. In this Article, all patients with HER2-positive gastric or gastro-oesophageal junction cancer with previous trastuzumab treatment who received trastuzumab deruxtecan were analysed together. The primary endpoints of the study were safety and preliminary activity (proportion of patients who achieved an objective response as assessed by the investigators). The activity evaluable set included all patients who received at least one dose of trastuzumab deruxtecan at the recommended doses for expansion, and for whom both baseline and post-treatment activity data were available. The safety analysis set included all patients who received at least one dose of trastuzumab deruxtecan at the recommended doses for expansion. Enrolment for patients with gastric or gastro-oesophageal junction cancer has completed. This trial is registered at ClinicalTrials.gov, number NCT02564900, and ClinicalTrials.jp, number JapicCTI-152978., Findings: Between Aug 28, 2015, and Aug 10, 2018, 44 patients with HER2-positive gastric or gastro-oesophageal junction cancer received at least one dose of trastuzumab deruxtecan at the recommended doses for expansion. All patients had at least one treatment-emergent adverse event. The most frequent grade 3 or worse treatment-emergent adverse events included anaemia (13 [30%]) and decreases in neutrophil (nine [20%]), platelet (eight [18%]), and white blood cell (seven [16%]) counts. Serious treatment-emergent adverse events occurred in 11 (25%) patients. There were four pneumonitis cases (three grade 2 and one grade 3). There were no drug-related deaths due to treatment-emergent adverse events. 19 (43·2%; 95% CI 28·3-59·0) of 44 patients had a confirmed objective response., Interpretation: Trastuzumab deruxtecan had a manageable safety profile and showed preliminary activity in heavily pretreated patients with HER2-positive gastric or gastro-oesophageal junction cancer. These results support further investigation of trastuzumab deruxtecan for HER2-positive gastric or gastro-oesophageal junction cancer post-trastuzumab., Funding: Daiichi Sankyo Co, Ltd., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

AT-rich interactive domain 1A (ARID1A) functions as a tumor suppressor and several therapeutic targets in ARID1A-mutated cancers are under development. Here, we investigated the prognostic value of ARID1A for gastric cancer and its association with expression of PD-L1 and p53. ARID1A expression was examined by immunohistochemistry and negative expression of ARID1A was detected in 39 (19.5%) of 200 cases in a test cohort and in 40 (18.2%) of 220 cases in a validation cohort. Negative expression of ARID1A was associated with worse overall survival in undifferentiated cases, particularly early-stage cases. Negative expression of ARID1A was detected in 11 (50%) of 22 PD-L1-positive cases and in 68 (17.1%) of 398 PD-L1-negative cases in a combined cohort. Negative expression of ARID1A was detected in 45 (22%) of 205 p53-positive cases and in 34 (15.8%) of 215 p53-negative cases in a combined cohort. In addition, expression of EZH2, a potential synthetic lethal target in ARID1A-mutated tumors, was detected in 79 ARID1A-negative cases. An ARID1A-knockdown gastric cancer cell line was subjected to microarray analysis, but no actionable targets or pathways were identified. The present results indicate that ARID1A may serve as an early-stage prognostic biomarker for undifferentiated gastric cancer.

Background: Primary gastric squamous cell carcinoma (SCC) is a very rare disease. The origin of this tumor remains unclear, although there are some hypotheses. A 60-year-old man consulted a previous physician complaining of upper abdominal pain. Esophagogastroduodenoscopy revealed type 2 gastric cancer, and the patient was referred to our hospital. After close examination, the patient was diagnosed as cStage IIA gastric adenocarcinoma, and distal gastrectomy was performed. Histochemical studies showed typical findings of SCC, and the tumor was surrounded by intestinal metaplasia. Immunohistochemical examination was positive for cytokeratin (CK) 5/6 and caudal-type homeobox protein 2 (CDX2) and negative for p63/p40., Conclusion: The results of immunostaining for CK5/6 supported that this tumor was SCC, but the question why p63/p40 were negative and CDX2 was positive still remained. Concerning about the origin of p63/p40 and CDX2, it was suggested that the tumor cells were not derived from ectopic squamous epithelium but from intestinal metaplasia. And tumor cells looked like homogeneous and squamous metaplasia was not observed. These findings supported the idea that these tumor cells arose from stem cells in the intestinal metaplasia of the stomach.

We encountered a case of type 4 gastric cancer with esophageal invasion that responded to neoadjuvant chemotherapy containing S-1 and oxaliplatin(SOX)followed by surgery, which could be curative resection. A 46-year-old man was referred to our hospital because of abnormal upper gastrointestinal series findings. He was diagnosed with type 4 advanced gastric cancer with esophageal invasion, cT4b(diaphragm)N2M0, Stage ⅢC, and 3 courses of neoadjuvant SOX therapy were administered. Adverse events were minor. After NAC, the primary lesion and lymph nodes showed marked reductions on CT; total gastrectomy and subtotal thoracic esophagectomy were performed. The pathological response to NAC was evaluated as Grade 2 in the primary tumor and Grade 3 in the lymph node; overall, NAC showed considerable antitumor effects. The final diagnosis was ypT3N0M0P0CY0H0, StageⅡA, and was judged as curatively resected. Currently, we are continuing to administer adjuvant chemotherapy containing S-1.

Background/aim: We evaluated the survival benefit of splenectomy in patients with esophagogastric junction (ECJ) carcinoma., Patients and Methods: We retrospectively examined clinicopathological and survival data for 60 surgically-treated patients with ECJ carcinoma., Results: The 5-year overall survival (OS) rate was 47%. Splenectomy was performed in 20 patients (30%). Multivariate Cox regression analysis revealed splenectomy (odds ratio (OR), 2.70; 95% confidence interval (CI)=1.06-7.17; p=0.04) and venous invasion (OR=3.03; 95%CI=1.20-9.27; p=0.02) as significant independent predictors of poorer OS. Splenic hilar lymph node metastasis was not observed. Multivariate logistic regression analysis identified perioperative blood transfusion (BTF) as a significant independent factor associated with splenectomy., Conclusion: The survival benefit of splenectomy in ECJ carcinoma patients may decrease with increasing frequency of perioperative BTF for blood loss. We recommend that splenectomy should be performed carefully when indicated by the extent or invasion of EGJ carcinoma., (Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

An 81-year-oldwoman with advancedgastric cancer was referredto our hospital. Preoperative contrast-enhancedCT revealeda roundcalcification of the splenic hilum with 15mm in diameter as a splenic artery aneurysm. She underwent transcatheter arterial embolization(TAE)for the splenic artery aneurysm. Celiac artery angiography showedcollateral arterial network of the spleen from left gastric artery. Surgery for the gastric cancer was performed1 4 days after TAE. We cut the right gastric andbilateral epigastric arteries. After the left gastric artery clamping, we performedintraoperative indocyanine green(ICG)fluorography. ICG fluorography confirmedthat the bloodflow of the upper thirdof the stomach andspleen were maintained. We safely performed distal gastrectomy, and the postoperative course was uneventful.

Background and Aim: Proton pump inhibitors (PPI) are effective at healing artificial ulcers after endoscopic submucosal dissection (ESD) for gastric neoplasms; however, the efficacy of vonoprazan is not completely understood. The aim of the present study was to determine the healing effect of vonoprazan on artificial ulcers post-gastric ESD relative to PPI., Methods: Thirty-five patients who underwent gastric ESD between April and November 2015 were treated with vonoprazan 20 mg/day for 4 weeks and subsequently underwent endoscopy for evaluation of ulcer size (V group). Ulcer contraction rate was determined by the following formula: ([ESD specimen size] - [ulcer size at 4 weeks after ESD])/(ESD specimen size) × 100%. We compared the results with those of a historical control group treated with esomeprazole 20 mg/day for 4 weeks after gastric ESD and subsequently measured their ulcer size (33 patients, E group) by propensity score-matching methods., Results: Sixty-two subjects were enrolled after propensity score-matching. Ulcer contraction rate at 4 weeks after ESD in the V group was significantly higher than that of the E group (97.7 ± 3.2% vs 94.5 ± 6.7%, respectively, P = 0.025). Number of subjects with a scar-stage ulcer (100% contraction rate) tended to be higher in the V group relative to the E group (32% [10 of 31] vs 13% [4 of 31], respectively, P = 0.070, McNemar's chi-squared test)., Conclusion: Vonoprazan has a faster post-gastric ESD artificial ulcer contraction rate than esomeprazole. Vonoprazan may supersede PPI in treating post-ESD artificial ulcers of the stomach., (© 2016 Japan Gastroenterological Endoscopy Society.)

Background: It is well known that in patients with sporadic nonampullary duodenal adenoma/carcinoma (SNADA) with no polyposis syndrome, including familial adenomataous polyposis, the rates of colorectal adenoma/carcinoma are high. However, the prevalence rates of other tumor types, for example, gastric cancer, in SNADA patients remain unknown. In this study, we aimed to analyze the prevalence rate of comorbid diseases in SNADA patients., Methods: We retrospectively analyzed 78 patients with SNADA treated by endoscopic resection between May 2005 and September 2014 at our institution., Results: Overall, 51 of the 78 (65.4%) SNADA patients had comorbid colorectal adenoma/carcinoma. Further, 10 of the 78 (12.8%) SNADA patients had comorbid gastric cancer, and all of them were positive for Helicobacter pylori infection. SNADA lesions were located significantly more frequently at the oral side of the major papilla in patients with H. pylori infection than in those without H. pylori infection (27 of 36 [75.0%] vs. 19 of 42 [45.2%], p = 0.008, chi-square test). In contrast, SNADA lesions were located significantly more frequently at the anal side of the major papilla in patients with colorectal adenoma/carcinoma than in those without colorectal adenoma/carcinoma (27 of 51 [52.9%] vs. 5 of 27 [18.5%], p = 0.003, chi-square test)., Conclusion: SNADA patients showed comorbidity with not only colorectal adenoma/carcinoma but also gastric cancer. H. pylori infection is known to cause gastric cancer and may influence tumorigenesis of SNADA lesions at the oral side of the major papilla.

Aim: To evaluate the recurrence risk for Siewert type II esophagogastric junction carcinoma treated with curative resection., Patients and Methods: We retrospectively analyzed clinicopathological and recurrence-free survival (RFS) data of 52 patients after curative resection for Siewert type II carcinoma focusing on the role of lymph node metastasis around the greater curvature or parapyloric area., Results: Recurrence was observed in 21 (40%) patients; the median time-to-recurrence was 11 months (range=3-33 months). According to multivariate Cox proportional hazard regression analysis, involvement of nodes no. 4sa, 4sb, 4d, 5 and/or 6 (odds ratio (OR)=6.62; 95% confidence interval (CI)=1.27-41.1; p=0.04) and younger age (OR=2.10; 95% CI=1.25-3.82; p<0.01) were significant independent risk factors affecting RFS., Conclusion: Involvement of no. 4-6 nodes appears to predict recurrence of Siewert type II carcinoma treated with curative resection. Patients with this risk factor may benefit from effective use of perioperative chemotherapy., (Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.)

Aim: To investigate the optimum period of treatment for post endoscopic submucosal dissection (ESD) ulcers., Methods: Patients who underwent ESD for gastric cancer were randomized to two groups and treated with esomeprazole 20 mg per day for 4 wk (4W group) or 2 wk (2W group). At 4 wk after ESD, we measured the size of the artificial ulcers by endoscopy and determined the ulcer healing rate, compared with the size of the ESD specimens. This randomized controlled trial study was approved by our ethics committee and registered in the UMIN Clinical Trial Registry., Results: A total of 60 consecutive patients were included in the study. All patients received rebamipide 300 mg per day for 4 wk. One patient in 2W group who showed bleeding within two weeks and received endoscopic treatment was excluded from further analysis. The numbers of patients with ulcers in the healing/scar stage in the 2W and 4W groups at 4 wk after ESD were 20/6 and 28/5, respectively, with no significant difference. The ulcer healing rate in the 2W and 4W groups were 96.1% [95% confidence interval (CI): 94.6%-97.55] vs 94.8% (95%CI: 92.6%-97.1%), respectively, with no statistical difference (UMIN000006951)., Conclusion: Two-wk treatment with a proton pump inhibitor is as effective as four-week treatment for healing post ESD ulcers.

Background: Endoscopic submucosal dissection (ESD) has become widely accepted as a standard treatment for gastric epithelial neoplasms. Antithrombotic agents are widely used to prevent thromboembolic disease. However, the feasibility of endoscopic procedures for patients using such agents has been rarely investigated. The aim of this study was to identify risk factors for post-operative bleeding after gastric ESD and to evaluate the relationship between the use of antithrombotic agents and post-operative bleeding., Methods: From June 2005 to March 2014, 413 patients with 425 gastric neoplasms were treated by ESD. The demographic and clinical parameters associated with post-operative bleeding were investigated. 83 patients receiving antithrombotic agents were separately assessed using various methods of administration during the ESD procedure. Post-operative bleeding that occurred within 5 days of ESD was defined as early post-operative bleeding, whereas subsequent bleeding was defined as delayed bleeding., Results: The overall post-operative bleeding rate was 4.7%. In patients with continued low-dose aspirin (LDA), heparin replacement (HR), or continued LDA along with HR, post-operative bleeding rates were 9.5%, 23.8%, and 25.0%, respectively. On multivariate analysis, a specimen size of ≥40 mm was a risk factor for early post-operative bleeding [odds ratio (OR) 6.08, 95% CI: 1.74-21.27], and HR and chronic kidney disease (CKD) requiring hemodialysis were risk factors for delayed bleeding (OR 12.23, 95% CI: 2.63-56.77 and OR 28.35, 95% CI: 4.67-172.11, respectively). Continued LDA was not a risk factor for post-operative bleeding., Conclusions: Large specimen size is a risk factor for early post-operative bleeding, and HR and CKD requiring hemodialysis are risk factors for delayed bleeding. Patients with risk factors should be carefully watched, allowing for the timing of post-operative bleeding after ESD.

Background/aim: To evaluate the potential risk of gastric tube reconstruction for Siewert type II esophagogastric junction carcinoma., Patients and Methods: We retrospectively analyzed clinicopathological and survival data of 41 patients who had undergone total gastrectomy for Siewert type II carcinoma, focusing on lymph node metastasis around the middle to lower greater curvature or parapyloric area., Results: Histological examination showed involvement of at least one lymph node in six patients (14%). Multivariate Cox proportional hazard regression analysis of seven clinicopathological variables showed that lymph node metastasis around the middle to lower greater curvature, or parapyloric area was the only significant independent unfavorable factor (odds ratio=6.62; 95% confidence interval=1.27-41.1; p=0.03) for survival. We identified no significant predictors of lymph node metastasis in analyzed patients., Conclusion: From an oncological point of view, we do not recommend routine gastric tube reconstruction for Siewert type II carcinoma.

Primary gastric choriocarcinoma is a rapidly growing neoplasm with an average survival of several months in untreated patients. Gastrectomy with lymph node dissection followed by chemotherapy is the treatment of choice. Regimens used for gastric adenocarcinoma are usually selected. However, median survival remains less than six months. In this case report, we describe a case of primary gastric choriocarcinoma with a clinical complete response to multidisciplinary treatment including surgery, chemotherapy, and radiofrequency ablation (RFA). The patient was originally referred for general malaise. Esophagogastroduodenoscopy demonstrated a large tumor occupying the fornix, and total gastrectomy with lymph node dissection was performed. Seven days later, multiple liver metastatic recurrences with high serum levels of beta-human chorionic gonadotropin (β-hCG) were recognized. Chemotherapy with a gonadal choriocarcinoma regimen consisting of etoposide, methotrexate, actinomycin D, cyclophosphamide, and vincristine (EMA/CO), was initiated. After three cycles, serum β-hCG decreased markedly and the tumors disappeared. Six months later, multiple lung metastatic recurrences were found. After one cycle of EMA/CO, only one nodule remained. Computed tomography-guided RFA was performed for this oligometastatic tumor. The patient has been alive with no evidence of disease for 10 years after the initial diagnosis. To the best of our knowledge, this patient with recurrent primary gastric choriocarcinoma has achieved the longest survival. The present case is the first report of choriocarcinoma metastatic to the lung successfully treated with RFA. From our retrospective analysis of recurrent or unresectable primary gastric choriocarcinoma, we propose that gonadal choriocarcinoma regimens can be considered as first-line for primary gastric choriocarcinoma.

A man visited to our hospital because of high grade fever. Computed tomography revealed multilocular space occupying lesion which were suspected liver abscess. Upper gastrointestinal endoscopy showed an advanced gastric cancer with an ulcer on antrum. Antibiotics decreased the level of CRP, concurrently with the reduction of liver space occupying lesion. While he underwent distal gastrectomy, pathological examination demonstrated the existence of bacterial foci and microabscesses on the surface of the gastric cancer. We speculate in this case that liver abscesses were formed by the infection of resident bacteria through portal vein.

A 60-year-old female was diagnosed as advanced gastric cancer with multiple bone, neck and mediastinal lymph node metastases. As a primary chemotherapy, she was treated with S-1(50 m g/body, twice daily for 4 weeks, followed by a 2- week rest). After 3 courses of S-1, she developed a disease progression with pulmonary lymphangitic carcinomatosis and disseminated intravascular coagulation(DIC). Therefore, she received second-line chemotherapy of irinotecan(CPT-11 150 mg/m2, biweekly). Within 3 weeks of starting the treatment, the clinical and laboratory signs of DIC were dramatically resolved. There have been no previous reports of irinotecan alone showing such remarkable effectiveness in a patient with 5- FU-resistant gastric cancer with DIC.

A 77-year-old man was admitted to our hospital complaining of general malaise, loss of appetite and hemoptysis. Chest X-ray film and computed tomography (CT) scan showed right-sided pleural effusion with lung tumor. Succeeding upper gastro-intestinal fiberscopy and cystoscopy revealed poorly-differentiated adenocarcinoma of the stomach and urothelial carcinoma of the bladder. Repeated treatment with 100 mg/body of S-1 on day 1 followed by 60 mg/m(2) of cisplatin on day 8 was effective in this patient.

Gastrointestinal stromal tumors (GISTs) are rare mesenchymal neoplasms with an annual incidence of approximately 10 to 20 per 1 million cases. Although pathologists have often observed incidental small GISTs in the stomach resected from patients with gastric cancer, no report on the real incidence of gastric GISTs is available. In this study, 100 whole stomachs resected from patients with gastric cancer were sectioned at 5-mm intervals and hematoxylin and eosin-stained slides (a mean of 130 slides for each case) were examined for microscopic GISTs. KIT (CD117), CD34, and desmin expression of the incidental tumors was evaluated by immunohistochemistry, and genomic DNA extracted from formalin-fixed and paraffin-embedded tumor tissues was analyzed for c-kit gene mutations in exon 11. In 35 of the 100 whole stomachs, we found 50 microscopic GISTs, all of which were positive for KIT and/or CD34 and negative for desmin. Most microscopic GISTs (45/50, 90%) were located in the upper stomach. Two of the 25 (8%) microscopic GISTs had c-kit gene mutations. Fifty-one leiomyomas with positive expression for desmin were observed in 28 of the 100 stomachs. Both leiomyomas and GISTs were found in 12 stomachs. These results indicate that microscopic GISTs are common in the upper portion of the stomach. Considering the annual incidence of clinical GISTs, only few microscopic GISTs may grow into a clinical size with malignant potential. Further studies are required to clarify the genetic events responsible for the transformation of microscopic GISTs to clinical GISTs.