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Abstract Metastatic gastric cancer (GC) presents significant clinical challenges due to its poor prognosis and limited treatment options. To address this, we conducted a targeted protein biomarker discovery study to identify markers predictive of metastasis in advanced GC (AGC). Serum samples from 176 AGC patients (T stage 3 or higher) were analyzed using the Olink Proteomics Target panels. Patients were retrospectively categorized into nonmetastatic, metastatic, and recurrence groups, and differential protein expression was assessed. Machine learning and gene set enrichment analysis (GSEA) methods were applied to discover biomarkers and predict prognosis. Four proteins (MUC16, CAIX, 5’-NT, and CD8A) were significantly elevated in metastatic GC patients compared to the control group. Additionally, GSEA indicated that the response to interleukin-4 and hypoxia-related pathways were enriched in metastatic patients. Random forest classification and decision-tree modeling showed that MUC16 could be a predictive marker for metastasis in GC patients. Additionally, ELISA validation confirmed elevated MUC16 levels in metastatic patients. Notably, high MUC16 levels were independently associated with metastatic progression in T3 or higher GC. These findings suggest the potential of MUC16 as a clinically relevant biomarker for identifying GC patients at high risk of metastasis.

Background/Aims: Synchronous multiple gastric cancer (SMGC) accounts for approximately 6% to 14% of gastric cancer (GC) cases. This study aimed to identify risk factors for SMGC. Methods : A total of 14,603 patients diagnosed with GC were prospectively enrolled. Data including age, sex, body mass index, smoking, alcohol consumption, family history, p53 expression, microsatellite instability, cancer classification, lymph node metastasis, and treatment were collected. Risk factors were analyzed using logistic regression analysis between a single GC and SMGC. Results : The incidence of SMGC was 4.04%, and that of early GC (EGC) and advanced GC (AGC) was 5.43% and 3.11%, respectively. Patients with SMGC were older (65.33 years vs 61.75 years, p

Introduction: Systemic chemotherapy is typically administered following radical gastrectomy for advanced stage. To attenuate systemic side effects, we evaluated the effectiveness of regional chemotherapy using paclitaxel, albumin-paclitaxel, and liposome-encapsulated albumin-paclitaxel via subserosal injection in rat models employing nuclear medicine and molecular imaging technology.Method: Nine Sprague Dawley rats were divided into three groups: paclitaxel (n = 3), albumin-paclitaxel nano-particles (APNs; n = 3), and liposome-encapsulated APNs (n = 3). [123I]Iodo-paclitaxel ([123I]I-paclitaxel) was synthesized by conventional electrophilic radioiodination using tert-butylstannyl substituted paclitaxel as the precursor. Albumin-[123I]iodo-paclitaxel nanoparticles ([123I]APNs) were prepared using a desolvation technique. Liposome-encapsulated APNs (L-[123I]APNs) were prepared by thin-film hydration using DSPE-PEG2000, HSPC, and cholesterol. The rats in each group were injected with each test drug into the subserosa of the stomach antrum. After predetermined times (30 min, 2, 4, 8 h, and 24 h), molecular images of nuclear medicine were acquired using single-photon emission computed tomography/computed tomography.Results: Paclitaxel, APNs, and L-APNs showed a high cumulative distribution in the stomach, with L-APNs showing the largest area under the curve. Most drugs administered via the gastric subserosal route are distributed in the stomach and intestines, with a low uptake of less than 1% in other major organs. The time to reach the maximum concentration in the intestine for L-APNs, paclitaxel, and APNs was 6.67, 5.33, and 4.00 h, respectively.Conclusion: These preliminary results imply that L-APNs have the potential to serve as a novel paclitaxel preparation method for the regional treatment of gastric cancer.

Abstract Obesity is considered a high-risk disease and a global epidemic, and the number of obese patients is rising at an alarming rate worldwide. High-fat diet-induced dysbiosis of the intestinal microbiota is considered an essential factor related to obesity. Bariatric surgery induces a sharp decrease in fat content and effectively improves the metabolism of obese individuals. Herein, we aimed to investigate the effects of a high-fat diet-induced obesity and the alterations in gastric and intestinal microbiota resulting from sleeve gastrectomy on clinical outcomes. We performed 16S sequencing of gastric and fecal samples obtained from rats in three treatment groups: normal chow diet, high-fat diet (HFD), and sleeve gastrectomy after HDF for 14 weeks. The area under the curve of fasting glucose and the levels of leptin and low-density lipoproteins were significantly different between groups. Microbial taxa that were highly correlated with several clinical parameters were identified for each group. Glyoxylate and dicarboxylate, taurine and hypotaurine, butanoate, nitrogen, and pyrimidine metabolism and aminoacyl-transfer ribonucleic acid biosynthesis were affected by bariatric surgery and were significantly associated with changes in the composition of gastric and fecal microbiomes. Connectivity and co-occurrence were higher in fecal samples than in gastric tissues. Our results elucidated the positive effects of sleeve gastrectomy in obesity and shed light on changes in the microbiomes of gastric and fecal samples.

Abstract Advancements in minimally invasive surgery has led to the development of several surgical instruments, including the ArtiSential®. This new instrument provides a greater range of motion and improved dexterity to laparoscopic procedures, making it an alternative option to traditional straight instruments, and the Da Vinci robot system. The purpose of this study is to compare the postoperative outcomes of a prospective cohort of patients who underwent laparoscopic gastrectomy using articulating instruments with those of a historical cohort of patients who underwent the same procedure using straight instruments. The study was designed as a prospective observational cohort study matched to a retrospective historical cohort using propensity score matching. The primary outcome was the rate of early complications within 90 days of surgery. Other outcomes included the operation time, estimated blood loss, time to first flatus, time to first soft fluid diet, hospital stay, and mortality. After propensity score matching, 41 patients were enrolled in both groups. The mean age was 62.4 ± 12.3 years in the conventional group and 63.5 ± 9.6 years in the artisential group (p = 0.647). Mean operative time was significantly shorter in the artisential group compared to the conventional group (136.1 min vs. 163.9 min, p = 0.032). The time to first soft fluid diet was also significantly shorter in the artisential group (2.2 days vs. 2.8 days, p = 0.030), but there was no significant difference in the time to first flatus and overall hospital stay. The incidence of early complications was lower in the artisential group, but the difference was not significant (24.4% vs 7.3%, p = 0.070). There was no mortality in either group. The use of articulating instruments for laparoscopic gastrectomy did not increase postoperative morbidity compared to straight laparoscopic instruments. The use of articulating instruments may be associated with faster bowel recovery and less early complications.

Background/Aims: There are few reports regarding mixed carcinoma, defined as a mixture of glandular and poorly cohesive components, in patients with gastric cancer (GC). The aim of this study was to evaluate the proportion and characteristics of mixed carcinoma in GC patients. Methods: A total of 7,215 patients diagnosed with GC at Seoul National University Bundang Hospital were enrolled from March 2011 to February 2020. GC was divided into four groups (well-moderately differentiated GC, poorly differentiated GC, poorly cohesive carcinoma, and mixed carcinoma). The proportion of each GC type and the clinicopathological features were analyzed and divided into early GC and advanced GC. Results: The proportion of mixed carcinoma was 10.9% (n=787). In early GC, submucosal invasion was the most common in poorly differentiated (53.7%), and mixed carcinoma ranked second (41.1%). Mixed carcinoma showed the highest proportion of lymph node metastasis in early GC (23.0%) and advanced GC (78.3%). In advanced GC, the rate of distant metastasis was 3.6% and 3.9% in well-moderately differentiated GC and mixed carcinoma, respectively, lower than that in poorly differentiated GC (6.4%) and poorly cohesive carcinoma (5.7%), without statistical significance. Conclusions: Mixed carcinoma was associated with lymph node metastasis compared to other histological GC subtypes. And it showed relatively common submucosal invasion in early GC, but the rates of venous invasion and distant metastasis were lower in advanced GC. Further research is needed to uncover the mechanism underlying these characteristics of mixed carcinoma (Trial registration number: NCT04973631).

Abstract Background We aimed to determine the molecular and immune microenvironment characteristics of HER2‐positive gastric cancer (GC) related to the patient's response to first‐line trastuzumab‐based treatment. Methods Eighty‐three cases of HER2‐positive advanced gastric adenocarcinoma patients treated with trastuzumab were enrolled. Targeted deep sequencing and transcriptome analysis were performed on selected 21 cases (exploration cohort) along with two post‐treatment samples. The results were compared between patients progressed before 6 months (Group 2) and others (Group 1), and were validated by FISH and immunohistochemistry in total cohort. Tumor‐infiltrating immune cells were evaluated using RNA sequencing data and multiplex immunohistochemistry. Progression‐free survival (PFS) analysis was performed. Results Group 1 showed frequent amplification of G1/S cell cycle checkpoint‐related genes and upregulated KEGG pathways related to cell proliferation. In contrast, Group 2 had more frequent EGFR, HER3, and MET amplification and higher RNA expression in immune‐related KEGG pathways than Group 1. In total cohort, significant predictors of better PFS were cell cycle‐related including CCNE1 amplification, Cyclin A and PLK1 overexpression, and decreased Cyclin D3 and HER3 expression (p

Background/Aims: The incidence and prognosis of gastric cancer (GC) shows sex difference. This study aimed to evaluate the effect of body mass index (BMI) on GC survival depending on sex. Methods: The sex, age, location, histology, TNM stages, BMI, and survival were analyzed in GC patients from May 2003 to February 2020 at the Seoul National University Bundang Hospital. Results: Among 14,688 patients, there were twice as many males (66.6%) as females (33.4%). However, under age 40 years, females (8.6%) were more prevalent than males (3.1%). Cardia GC in males showed a U-shaped distribution for underweight (9.6%), normal (6.4%), overweight (6.1%), obesity (5.6%), and severe obesity (9.3%) but not in females (p=0.003). Females showed decreased proportion of diffuse-type GC regarding BMI (underweight [59.9%], normal [56.8%], overweight [49.5%], obesity [44.8%], and severe obesity [41.7%]), but males did not (p

Background/Aims: Less invasive surgical treatment is performed in East Asia to preserve postoperative digestive function and reduce complications such as postgastrectomy syndromes, but there is an issue of metachronous gastric cancer (GC) in the remaining stomach. This study aimed to analyze the incidence of metachronous GC and its risk factors in patients who had undergone partial gastrectomy. Methods: A total of 3,045 GC patients who had undergone curative gastric partial resection at Seoul National University Bundang Hospital were enrolled and analyzed retrospectively for risk factors, including age, sex, smoking, alcohol, Helicobacter pylori status, family history of GC, histological type, and surgical method. Results: Metachronous GC in the remaining stomach occurred in 35 of the 3,045 patients (1.1%): 23 in the distal gastrectomy group (18 with Billroth-I anastomosis, five with Billroth-II anastomosis), seven in the proximal gastrectomy (PG) group, and five in the pylorus-preserving gastrectomy (PPG) group. Univariate and multivariate Cox regression analyses showed that age ≥60 years (p=0.005) and surgical method used (PG or PPG, p

Abstract Since Dr. Kitano introduced laparoscopic distal gastrectomy for early gastric cancer in 1994, there have been remarkable advances in minimally invasive surgery (MIS) for gastric cancer, including robotic surgery. With the efforts of many clinical researchers and consenting patients, medical knowledge and evidence for laparoscopic surgery in gastric cancer have accumulated. Although many gastric surgeons are comfortable with the clinical application of laparoscopic surgery for early gastric cancer, the adoption of MISs for advanced gastric cancer remains controversial. In this review article, we describe the current status and evidence of MIS from an evidence‐based medicine viewpoint and explore the feasibility and effectiveness of MIS for advanced gastric cancer in the real world.

The utilization of Ni-rich layered LiNixCoyMn1--x--yO2 (NCM, x > 0.6) cathodes in all-solid-state batteries (ASSBs) holds great promise due to their high practical capacities. However, these cathodes suffer from a rapid capacity degradation due to unwanted interface side reactions with solid electrolyte. To mitigate this issue, an ultrathin (~0.9 nm) and amorphous Al2O3 coating layer is applied to the Ni-rich NCM cathodes using atomic layer deposition (ALD). Remarkably, this nanoscale coating leads to minimal changes in the initial capacity while significantly improving the cycle retention. Through a variety of analytical techniques, we demonstrate that the Al2O3-coated NCM cathode exhibits high cycle stability by reducing the formation of insulating by-products on the surface and suppressing the irreversible phase transition during cycling. This work demonstrates the potential of employing a thin oxide coating to address the key degradation factors in Ni-rich NCM cathodes, advancing the prospects for future ASSBs. [ABSTRACT FROM AUTHOR]

Abstract The advantages of laparoscopic resection over open surgery in the treatment of gastric gastrointestinal stromal tumor (GIST) are not conclusive. This study aimed to evaluate the postoperative and oncologic outcome of laparoscopic resection for gastric GIST, compared to open surgery. We retrospectively reviewed the prospectively collected database of 1019 patients with gastric GIST after surgical resection at 13 Korean and 2 Japanese institutions. The surgical and oncologic outcomes were compared between laparoscopic and open group, through 1:1 propensity score matching (PSM). The laparoscopic group (N = 318) had a lower rate of overall complications (3.5% vs. 7.9%, P = 0.024) and wound complications (0.6% vs. 3.1%, P = 0.037), shorter hospitalization days (6.68 ± 4.99 vs. 8.79 ± 6.50, P

Abstract Laparoscopic sleeve gastrectomy is the most frequently performed surgical intervention in patients with morbid obesity. Single-port sleeve gastrectomy (SPSG) and reduced-port sleeve gastrectomy (RPSG) are increasingly reported in the literature. This study compared the short-term outcomes of SPSG, RPSG, and conventional laparoscopic sleeve gastrectomy (CLSG). This is a single-center retrospective study of 238 morbidly obese patients, of whom 148 (62.2%) patients completed follow-up one year after surgery. Propensity score matching was performed on factors influencing the choice of approach, and fifty patients from the SPSG + RPSG and CLSG groups were successfully matched. The groups were comparable in postoperative weight loss, morbidity, pain, and resolution of obesity-related comorbidities. The percentage of excess weight loss after one year was 90.0% in the SPSG + RPSG group and 75.2% in the CLSG group (P

Abstract Background Natural killer (NK) cells mediate the anti-tumoral immune response as an important component of innate immunity. The aim of this study was to investigate the prognostic significance and functional implication of NK cell-associated surface receptors in gastric cancer (GC) by using multiplex immunohistochemistry (mIHC). Methods We performed an mIHC on tissue microarray slides, including 55 GC tissue samples. A total of 11 antibodies including CD57, NKG2A, CD16, HLA-E, CD3, CD20, CD45, CD68, CK, SMA, and ki-67 were used. CD45 + CD3-CD57 + cells were considered as CD57 + NK cells. Results Among CD45 + immune cells, the proportion of CD57 + NK cell was the lowest (3.8%), whereas that of CD57 + and CD57- T cells (65.5%) was the highest, followed by macrophages (25.4%), and B cells (5.3%). CD57 + NK cells constituted 20% of CD45 + CD57 + immune cells while the remaining 80% were CD57 + T cells. The expression of HLA-E in tumor cells correlated with that in tumoral T cells, B cells, and macrophages, but not CD57 + NK cells. The higher density of tumoral CD57 + NK cells and tumoral CD57 + NKG2A + NK cells was associated with inferior survival. Conclusions Although the number of CD57 + NK cells was lower than that of other immune cells, CD57 + NK cells and CD57 + NKG2A + NK cells were significantly associated with poor outcomes, suggesting that NK cell subsets play a critical role in GC progression. NK cells and their inhibitory receptor, NKG2A, may be potential targets in GC.

Abstract Background Preoperative sarcopenia is associated with a poor long‐term prognosis in patients with gastric cancer (GC). Most GC patients rapidly lose muscle mass after gastrectomy. This retrospective cohort study analysed the effect of postoperative muscle loss and surgery‐induced sarcopenia on the long‐term outcomes of patients with GC. Methods Preoperative and postoperative 1 year abdominal computed tomography scans were available for 1801 GC patients who underwent curative gastrectomy between January 2009 and December 2013 at Seoul National University Bundang Hospital. The patients were categorized into normal, presarcopenia, and sarcopenia groups according to the skeletal muscle index (SMI) measured on computed tomography scans. Patients who were not sarcopenic prior to gastrectomy but became sarcopenic after surgery were defined as the surgery‐induced sarcopenia group. Results There were 1227 men and 574 women included in the study. The mean age of the patients was 59.5 ± 12.3 years. Multivariable Cox‐regression analyses showed that preoperative SMI was not associated with overall survival (OS). However, postoperative sarcopenia was associated with significantly worse OS only in men [hazard ratio (HR), 1.75; 95% confidence interval (CI), 1.08–2.85]. SMI loss was an independent risk factor for OS in the entire cohort and in men (HR, 1.01; 95% CI, 1.00–1.02, for the entire cohort; HR, 1.02; 95% CI, 1.01–1.04, for men). The surgery‐induced sarcopenia group was associated with significantly higher mortality (HR, 1.84; 95% CI, 1.16–2.90, for the cohort; HR, 2.73; 95% CI, 1.54–4.82, for men), although SMI loss and surgery‐induced sarcopenia were not risk factors in women. Similar results were obtained for relapse‐free survival. Conclusions Postoperative muscle mass loss and surgery‐induced sarcopenia are prognostic factors for survival in patients with GC. Impact of postoperative muscle mass loss and surgery‐induced sarcopenia on survival outcomes is dependent on the sex.

PurposeThe discrepancy between preoperative and final pathological staging has been a long-standing challenge for the application of clinical trials or appropriate treatment options. This study aimed to demonstrate the accuracy of preoperative staging of locally advanced gastric cancer using data from a large-scale randomized clinical trial.Materials and methodsOf the 1050 patients enrolled in the clinical trial, 26 were excluded due to withdrawal of consent (n = 20) or non-surgery (n = 6). The clinical and pathological staging was compared. Risk factor analysis for underestimation was performed using univariate and multivariate analyses.ResultsRegarding T staging by computed tomography, accuracy rates were 74.48, 61.62, 58.56, and 85.16% for T1, T2, T3 and T4a, respectively. Multivariate analysis for underestimation of T staging revealed that younger age, ulcerative gross type, circular location, larger tumor size, and undifferentiated histology were independent risk factors. Regarding nodal status estimation, 54.9% of patients with clinical N0 disease were pathologic N0, and 36.4% of patients were revealed to have pathologic N0 among clinical node-positive patients. The percentage of metastasis involvement at the D1, D1+, and D2 lymph node stations significantly increased with the advanced clinical N stage. Among all patients, 29 (2.8%), including 26 with peritoneal seeding, exhibited distant metastases.ConclusionsEstimating the exact pathologic staging remains challenging. A thorough evaluation is mandatory before treatment selection or trial enrollment. Moreover, we need to set a sufficient case number when we design the clinical trial considering the stage migration.

Several trials have documented the favorable safety profile, and promising clinical results of pressurized intraperitoneal aerosol chemotherapy (PIPAC) directed treatment in different types of peritoneal malignancies. However, until the results of randomized trials are available, the quality of documentation and acceptance by the users may be improved through a worldwide registry. The International Society for the Study of Pleura and Peritoneum (www.ISSPP.org) facilitated this process by creating a dedicated focus group and providing the funding needed for the creation and implementation of an international database. This article describes the design and the journey of establishing this international database and the first, preliminary results from the ISSPP PIPAC online database.

Purpose: Peritoneal carcinomatosis (PC) presents a major challenge in the treatment of late-stage, solid tumors, with traditional therapies limited by poor drug penetration. We evaluated a novel hyperthermic pressurized intraperitoneal aerosol chemotherapy (HPIPAC) system using a human abdominal cavity model for its efficacy against AGS gastric cancer cells. Materials and Methods: A model simulating the human abdominal cavity and AGS gastric cancer cell line cultured dishes were used to assess the efficacy of the HPIPAC system. Cell viability was measured to evaluate the impact of HPIPAC under 6 different conditions: heat alone, PIPAC with paclitaxel (PTX), PTX alone, normal saline (NS) alone, heat with NS, and HPIPAC with PTX. Results: Results showed a significant reduction in cell viability with HPIPAC combined with PTX, indicating enhanced cytotoxic effects. Immediately after treatment, the average cell viability was 66.6%, which decreased to 49.2% after 48 hours and to a further 19.6% after 120 hours of incubation, demonstrating the sustained efficacy of the treatment. In contrast, control groups exhibited a recovery in cell viability; heat alone showed cell viability increasing from 90.8% to 94.4%, PIPAC with PTX from 82.7% to 89.7%, PTX only from 73.3% to 74.8%, NS only from 90.9% to 98.3%, and heat with NS from 74.4% to 84.7%. Conclusions: The HPIPAC system with PTX exhibits a promising approach in the treatment of PC in gastric cancer, significantly reducing cell viability. Despite certain limitations, this study highlights the system’s potential to enhance treatment outcomes. Future efforts should focus on refining HPIPAC and validating its effectiveness in clinical settings. [ABSTRACT FROM AUTHOR]

The prevalence of obesity has increased steadily in Korea as well as worldwide, and bariatric surgery is the most powerful treatment modality for morbid obesity. However, fear of invasive procedures means most patients prefer less invasive procedures. New treatment modalities for obesity are emerging, but in Korea, only one traditional gastric balloon is approved by the government. Although it is difficult to introduce new techniques in Korea because of the high entry barrier presented by the country’s national health insurance system, it is important for physicians and surgeons to be aware of new obesity treatment modalities.

Abstract Background Frail older adults are at increased risk of post‐operative morbidity compared with robust counterparts. Simple methods testing frailty such as grip strength or gait speed have shown promising results for predicting post‐operative outcome, but there is a debate regarding the most appropriate and precise frailty assessment method. We compared the predictive value of multidimensional frailty score (MFS) with grip strength, gait speed, or conventional risk stratification tool for predicting post‐operative complications in older surgical patients. Methods From January 2016 to June 2017, 648 older surgical patients (age ≥ 65 years) were included for analysis. MFS was calculated based on the preoperative comprehensive geriatric assessment. Grip strength and gait speed were measured before surgery. The primary outcome was a composite of post‐operative complications (e.g. pneumonia, urinary tract infection, delirium, acute pulmonary thromboembolism, and unplanned intensive care unit admission). The secondary outcome was the 6 month all‐cause mortality. Results Among 648 patients (mean age 76.6 ± 5.4 years, 52.8% female), 66 (10.2%) patients experienced post‐operative complications, and the 6 month mortality was 3.9% (n = 25). Grip strength, gait speed, MFS, and American Society of Anesthesiologists (ASA) classification could predict post‐operative complication but only MFS (hazard ratio = 1.581, 95% confidence interval 1.276–1.959, P < 0.001) could predict 6 month mortality after adjustment. MFS (C‐index = 0.750) had a superior prognostic utility compared with age (0.638, P = 0.008), grip strength (0.566, P < 0.001), and ASA classification (0.649, P = 0.004). MFS improved the predictive value on age [C‐index of 0.638 (age) vs. 0.758 (age + MFS), P < 0.001] and ASA classification [C‐index of 0.649 (ASA) vs. 0.765 (ASA + MFS), P < 0.001] for post‐operative complication; however, gait speed or grip strength did not provide additional prognostic value in both age and ASA. Conclusions Multidimensional frailty score based on preoperative comprehensive geriatric assessment showed better utility than age, grip strength, gait speed, or ASA classification for predicting post‐operative complication and 6 month mortality. MFS also showed incremental predictive ability for post‐operative complications with the addition of age and ASA classification. Accordingly, MFS is superior to grip strength or gait speed for predicting complications among older surgical patients.

Purpose The present study aimed to evaluate atypical lymph node metastasis rates according to tumor depth, size, and location in patients with gastric cancer. Methods A total of 727 gastric adenocarcinoma patients, with metastasis to 1 or 2 lymph nodes, who underwent radical gastrectomy with curative intent from May 2003 to May 2017, were enrolled in this study. The characteristics of atypical (skip or transversal) metastases were evaluated according to the following risk factors: longitudinal versus circumferential location, size, and T stage of the tumor. Results The rates of skip and transversal metastases were 8.4% and 15.5%, respectively. Skip metastases were present throughout, regardless of the primary tumor location. On the contrary, transversal metastases of gastric cancer were most frequently observed in the lower third region (19.5%, P=0.002). When the size of the tumor is large (>4 cm), transversal metastasis was found to be significantly more common (P=0.035), compared with skip metastasis, which was less common (P=0.011). There was no significant correlation between atypical metastases and tumor depth. Conclusion Lower and larger tumors were more likely to have transversal metastases compared with others; however, skip metastases were less common in large tumors.

Peripheral regulatory T cells (pTregs) are a highly immunosuppressive fraction of CD4+ T cells. We aimed to evaluate the clinical significance of pTregs in patients with gastric cancer and to determine the correlation between pTregs and immune cell infiltration in tumor microenvironment. pTregs status was determined by assessing the pTreg/total T-cell ratio (ratio of Foxp3 Treg-specific demethylated region (TSDR) to CD3G/CD3D demethylation, so-called Cellular Ratio of Immune Tolerance "ImmunoCRIT") using methylation analyses in 433 patients with gastric cancer who received curative surgery. Among 422 evaluable patients, 230 (54.5%) had high ImmunoCRIT (> 21.0). Patients with high ImmunoCRIT had significantly shorter disease-free survival (DFS) and overall survival (OS) than those with high ImmunoCRIT (p = 0.030, p = 0.008, respectively). In multivariate analysis, high ImmunoCRIT kept a prognostic role for shorter OS (hazard ratio [HR] 1.9, 95% confidence interval [CI] 1.4-2.9; p = 0.005). CD3+ cell density and CD4+ cell density was significantly higher within the tumor in high ImmunoCRIT group than those in low ImmunoCRIT group (CD3+ cell, 202.12/mm2 vs. 172.2/mm2, p = 0.029; CD4+ cell, 56.5/mm2 vs. 43.5/mm2, p = 0.007). In conclusion, the peripheral ImmunoCRIT determined by epigenetic methylation analysis provides prognostic information in resected gastric tumors.

We sought to determine the clinicopathological significance of PD-1, LAG3, and TIM3 in gastric cancer (GC) by examining their expression and immune context. Immunohistochemistry (IHC) for PD-1, TIM3, LAG3, and tumor-infiltrating immune cell (TIIC) markers was performed in 385 stage II/III GCs. Epstein-Barr virus (EBV) and microsatellite stability (MSI) testing were performed for molecular classification. Chromogenic multiplex IHC (mIHC) for PD1, TIM3, LAG3, CD3, CD8, FOXP3, CD68, and cytokeratin was performed in 58 of the total samples. PD-1, LAG3, and TIM3 expression in TIICs was observed in 91 (23.6%), 193 (50.1%), and 257 (66.8%) GCs by single IHC, respectively. The expression was associated with EBV+ and MSI-H molecular subtypes (p ≤ 0.001). A positive expression of LAG3 in the invasive margin of the tumor was associated with better prognosis in univariate (p = .020) and multivariate (p = .026) survival analyses. The expression of different immune checkpoint receptors (ICRs) was significantly positively correlated. Dual or triple ICR expression was more frequent in high PD-1 and TIM3 density groups than in low-density groups by mIHC (all p ≤ 0.05). ICRs were mainly expressed in CD3+CD8+ and CD3+CD8− T cells. Fifty-eight GCs were classified into three groups by clustering analysis based on mIHC, and the group with the highest ICR expression in TIICs showed significantly better outcomes in progression-free survival (p = .020). In GC, PD-1, LAG3, and TIM3 expression is positively correlated and associated with better prognosis. Our study provides information for the application of effective immune checkpoint inhibitors against GC.

Purpose Bone metastasis (BM) adversely affects the prognosis of gastric cancer (GC). We investigated molecular features and immune microenvironment that characterize GC with BM compared to GC without BM. Materials and Methods Targeted DNA and whole transcriptome sequencing were performed using formalin-fixed paraffin-embedded primary tumor tissues (gastrectomy specimens) of 50 GC cases with distant metastases (14 with BM and 36 without BM). In addition, immunohistochemistry (IHC) for mucin-12 and multiplex IHC for immune cell markers were performed. Results Most GC cases with BM had a histologic type of poorly cohesive carcinoma and showed worse overall survival (OS) than GC without BM (p < 0.05). GC with BM tended to have higher mutation rates in TP53, KDR, APC, KDM5A, and RHOA than GC without BM. Chief cell-enriched genes (PGA3, PGC, and LIPF), MUC12, MFSD4A, TSPAN7, and TRIM50 were upregulated in GC with BM compared to GC without BM, which was correlated with poor OS (p < 0.05). However, the expression of SERPINA6, SLC30A2, PMAIP1, and ITIH2 were downregulated in GC with BM. GC with BM was associated with PIK3/AKT/mTOR pathway activation, whereas GC without BM showed the opposite effect. The densities of helper, cytotoxic, and regulatory T cells did not differ between the two groups, whereas the densities of macrophages were lower in GC with BM (p < 0.05). Conclusion GC with BM had different gene mutation and expression profiles than GC without BM, and had more genetic alterations associated with a poor prognosis. [ABSTRACT FROM AUTHOR]

Recently, the incidence of upper third gastric cancer has increased, and with it the number of endoscopic submucosal dissection (ESD) procedures performed has been increasing. However, if ESD is not indicated or non-curable, surgical treatment may be necessary. In the case of lower third gastric cancer, it is possible to preserve the upper part of the stomach; however, in the case of upper third gastric cancer, total gastrectomy is still the standard treatment option, regardless of the stage. This is due to the complications associated with upper third gastric cancer, such as gastroesophageal reflux after proximal gastrectomy rather than oncologic problems. Recently, the introduction of the double tract reconstruction method after proximal gastrectomy has become one of the surgical treatment methods for upper third early gastric cancer. However, since there has not been a prospective comparative study evaluating its efficacy, the ongoing multicenter prospective randomized controlled trial (KLASS-05) comparing laparoscopic proximal gastrectomy with double tract reconstruction and laparoscopic total gastrectomy is expected to be important for determining the future of treatment of upper third early gastric cancer.

Background/AimsHelicobacter pylori eradication is recommended in patients with early gastric cancer. However, the possibility of spontaneous regression raises a question for clinicians about the need for “retesting” postoperative H. pylori status.Methods : Patients who underwent curative gastrectomy at Seoul National University Bundang Hospital and had a positive H. pylori status without eradication therapy at the time of gastric cancer diagnosis were prospectively enrolled in this study. H. pylori status and atrophic gastritis (AG) and intestinal metaplasia (IM) histologic status were assessed pre- and postoperatively.Results : One hundred forty patients (mean age, 59.0 years; 60.7% male) underwent subtotal gastrectomy with B-I (65.0%), B-II (27.1%), Roux-en-Y (4.3%), jejunal interposition (0.7%), or proximal gastrectomy (4.3%). Preoperative presence of AG (62.9%) and IM (72.9%) was confirmed. The mean period between surgery and the last endoscopic follow-up was 38.0±25.6 months. Of the 140 patients, 80 (57.1%) were found to be persistently positive for H. pylori, and 60 (42.9%) showed spontaneous negative conversion at least once during follow-up. Of these 60 patients, eight (13.3%) showed more complex postoperative dynamic changes between negative and positive results. The spontaneous negative conversion group showed a trend of having more postoperative IM compared to the persistent H. pylori group.Conclusion : sA high percentage of spontaneous regression and complex dynamic changes in H. pylori status were observed after partial gastrectomy, especially in individuals with postoperative histological IM. It is better to consider postoperative eradication therapy after retesting for H. pylori.

Objective: The aim of this study was to audit the 22 items and assessed each item's predictive value on surgical outcomes. Background: The KLASS-02 trial revealed that the oncologic outcomes of laparoscopic distal gastrectomy are not inferior to open distal gastrectomy in patients with advanced gastric cancer. The surgeons participating in this trialwere chosen based on the assessment scores from the KLASS-02-QC trial, which used 22 items for standardization of D2 lymphadenectomy and quality control. Methods: We reviewed proficiency scores (PSs) for 22 items for 20 surgeons who participated in KLASS-02. The surgeons were divided into 2 groups according to PS, and the perioperative outcomes of 924 patients enrolled in KLASS-02 were compared between groups. Each item's predictive value for perioperative outcome was then assessed using multivariable regression models. Results: Of the total 924 patients, 529 were operated on by high-score surgeons (high PS) and 395 were operated on by low-score surgeons (low-PS). High-PS group had less intraoperative blood loss, longer operation times, and fewer complications,major complications, reoperations, and shorter first flatus and hospital stay than low-PS group (P=0.006, P<0.001, P<0.001, P<0.001, P=0.042, P=0.013, and P<0.001, respectively). Some items used in KLASS-02-QC predicted perioperative outcomes, such as intraoperative blood loss, major complications, reoperation, and hospital stay. Conclusions: Although this study only analyzed data associated with qualified surgeons, the 22 items effectively assessed the surgeons based on PS. A high score was associated with longer operation times, but better perioperative outcomes. [ABSTRACT FROM AUTHOR]

Purpose: According to the American Joint Committee on Cancer cancer staging system, positive peritoneal washing cytology (PWC) indicates stage IV gastric cancer. However, rapid intraoperative diagnosis of PWC has no established reliable method. This study evaluated and compared the diagnostic accuracy of the Shorr and the modified ultrafast Papanicolaou (MUFP) methods for intraoperative PWC. Materials and Methods: This study included patients with gastric cancer who were clinically diagnosed with stage cT3 or higher. The Shorr and MUFP methods were performed on all PWC specimens, and the results were compared with those of conventional Papanicolaou (PAP) staining with carcinoembryonic antigen immunohistochemistry. Sensitivity, specificity, and partial likelihood tests were used to compare the 2 methods. Results: Forty patients underwent intraoperative PWC between November 2019 and August 2021. The average time between specimen reception and slide preparation using Shorr and MUFP methods was 44.4±4.5 minutes, and the average time between specimen reception and pathologic diagnosis was 53.9±8.9 minutes. Eight patients (20.0%) had positive cytology in PAP staining. The Shorr method had a sensitivity of 75.0% and specificity of 93.8%; the MUFP method had 62.5% sensitivity and 100.0% specificity. The area under the curve was 0.844 for Shorr and 0.813 for MUFP. In comparing the C-indices of each method with overall survival, no difference was found among the Shorr, MUFP, and conventional PAP methods. Conclusions: The Shorr and MUFP methods are acceptable for the intraoperative diagnosis of PWC in advanced gastric cancer. [ABSTRACT FROM AUTHOR]