Gastric cancer (GC) is a globally prevalent malignancy with a particularly heavy burden in China. Helicobacter pylori ( H. pylori ) is a Group I carcinogen for GC, with a higher seroprevalence rate indicating a higher GC incidence. However, only approximately 3% of the individuals with H. pylori infection eventually develop GC, and about 2.6% still progress to GC even 10-20 years after the eradication of H. pylori . Thus, the pathogenic mechanism of H. pylori for GC must be elucidated, and high-risk individuals precisely identified. Furthermore, GC can occur even in individuals who have never been infected with H. pylori . As H. pylori infection rates decline, the proportion of H. pylori -negative GC cases is increasing annually, gaining significant research attention. In this review, potential pathogenic mechanisms of H. pylori infection are explored from the aspects of H. pylori virulence factors and host factors (genetic susceptibility and immune microenvironment). Possible risk factors for H. pylori -negative GC include infections by other microorganisms (e.g., bacteria, fungi, and viruses), autoimmune gastritis, bile reflux, genetic mutations, and environmental factors. We aim to review the potential mechanisms for GC with varying H. pylori infection statuses, identify the high-risk individuals, and pose questions that need to be addressed. In the future, as the prevalence of H. pylori infection gradually decreases, GC prevention and management must evolve to address host-specific factors and the growing challenge of H. pylori -negative GC by integrating multidisciplinary perspectives.
Stomach Neoplasms/genetics* ; Humans ; Helicobacter Infections/complications* ; Helicobacter pylori/pathogenicity* ; Risk Factors

OBJECTIVE: To explore the changes of CKLF-like MARVEL transmembrane domain-containing 6 (CMTM6) and programmed death-ligand 1 (PD-L1) expression in gastric mucosal epithelial cells after Helicobacter pylori infection and the regulation of CMTM6 on PD-L1, and to analyze the mRNA expression differences before and after CMTM6 gene knock-out in helicobacter pylori infected gastric epithelial cells by microarray analysis. METHODS: The standard Helicobacter pylori strain ATCC 26695 was co-cultured with human gastric epithelial cell GES-1 for 6, 24 and 48 hours, and the mRNA and protein levels of CMTM6 and PD-L1 were detected by real-time quantitative PCR and Western blot. Using CRISPR/Cas9 to construct CMTM6 gene knockout plasmid and knockout CMTM6 gene of GES-1 cells. Helicobacter pylori was co-cultured with CMTM6 gene knockout and wild type GES-1 cells for 48 hours to detect PD-L1 transcription and protein level changes, and CMTM6 gene knockout GES-1 cells were treated with the proteasome inhibitor MG-132 to detect the changes in PD-L1 protein levels. Agilent Human ceRNA Microarray 2019 was used to detect the differentially expressed genes in CMTM6 gene knockout and wild-type GES-1 cells co-cultured with Hp for 48 hours, and the signal pathway of differentially expressed genes enrichment was analyzed by Kyoto Encyclopedia of Genes and Genomes (KEGG) database. RESULTS: The mRNA and protein levels of CMTM6 and PD-L1 in GES-1 cells were significantly up-regulated after Helicobacter pylori infection, and CMTM6 mRNA was most significantly up-regulated 48 hours after infection. After CMTM6 gene knockout, the CD274 gene transcription level of Helicobacter pylori infected GES-1 cells did not change significantly, but PD-L1 protein level was significantly down-regulated, and the PD-L1 level increased after the application of proteasome inhibitor MG-132. After CMTM6 gene knockout, 67 genes had more than two times of differential expression. The transcription levels of TMEM68, FERMT3, GPR142, ATP6V1FNB, NOV, UBE2S and other genes were significantly down-regulated. The transcription levels of PCDHGA6, CAMKMT, PDIA2, NTRK3, SPOCK1 and other genes were significantly up-regulated. After CMTM6 gene knockout, ubiquitin-conjugating enzyme E2S (UBE2S) gene expression was significantly down-regulated, which might affect protein ubiquitination degradation. After CMTM6 gene knockout, adrenoceptor alpha 1B (ADRA1B), cholinergic receptor muscarinic 1 (M1), CHRM1, platelet activating factor receptor (PTAFR) gene expression was significantly up-regulated. CONCLUSION Helicobacter pylori infection up-regulates the expression level of CMTM6 in gastric mucosa cells, and CMTM6 can stabilize PD-L1 and maintain the protein level of PD-L1. CMTM6 gene knockout may affect biological behaviors such as protein ubiquitination and cell surface receptor expression.
Humans ; MARVEL Domain-Containing Proteins/metabolism* ; Helicobacter pylori/physiology* ; B7-H1 Antigen/genetics* ; Helicobacter Infections/metabolism* ; Epithelial Cells/metabolism* ; Gastric Mucosa/metabolism* ; Chemokines/metabolism* ; Cell Line ; Gene Knockout Techniques ; Myelin Proteins

Objective:To investigate the endoscopic and pathological characteristics of metachronous early gastric cancer (EGC) after endoscopic submucosal dissection (ESD) for EGC.Methods:Data of 451 consecutive EGC patients treated with ESD at the Department of Gastroenterology, Peking University Third Hospital between 1 January, 2005 and 31 December, 2022 were retrospectively collected, of which 252 patients who met the criteria and had endoscopic follow-up ≥ 1 year were enrolled in the retrospective dynamic cohort. Multivariate Cox regression analysis was used to identify independent risk factors for metachronous EGC after ESD. Pearson's contingency coefficient was applied to analyze endoscopic correlation between the index and metachronous lesions. T-test, χ2 test, and Fisher exact test were used to compare endoscopic pathological features between index and metachronous lesions, the proportion of lesions meeting absolute ESD indication and their maximum diameters between patients undergoing annual vs bi-annual follow-up. Kaplan-Meier analysis assessed the cumulative incidence of metachronous EGC. Results:During a median follow-up of 40 months, 26 patients [10.3% (26/252)] developed metachronous EGC, with a mean interval of 43.9 months. Multivariate Cox regression identified the independent risk factors of index lesions including location in the middle third of the stomach ( HR=3.783, 95% CI: 1.300-11.011, P=0.015), in the anterior wall ( HR=3.934, 95% CI: 1.113-13.904, P=0.033), and the maximum diameter <15 mm ( HR=3.034, 95% CI: 1.074-8.571, P=0.036). Pearson's contingency coefficient showed no significant concordance between index and metachronous lesions for vertical location (C=0.375, P=0.372), horizontal location (C=0.508, P=0.434), gross morphology (C=0.287, P=0.675), or ulcer presence (C=0.194, P=0.313). Compared to index lesions, metachronous lesions were more frequently located on the posterior wall (lesser curvature/greater curvature/anterior wall/posterior wall: 11/2/1/12 VS 96/49/46/61, P=0.031), more often differentiated (differentiated/undifferentiated: 26/0 VS 214/38, P=0.032), and smaller in maximum diameter (8.08±5.99 mm VS 13.95±10.26 mm, t=4.383, P<0.001). No significant differences were observed between patients undergoing annual vs bi-annual follow-up in the proportion of metachronous lesions meeting absolute ESD indication (14/16 VS 9/9, P=0.520) or in maximum diameter (8.11±6.94 mm VS 6.67±4.35 mm, t=-0.275, P=0.535). The cumulative incidence curve of metachronous EGC plateaued after 10 years. Conclusion:Patients with EGC located in the middle third of the stomach, in the anterior wall, or of smaller diameter need intensive endoscopic surveillance after ESD. Posterior wall deserves particular attention during follow-up, with annual endoscopy recommended for at least 10 years post-ESD.

Objective:To explore and evaluate the optimization and application of case-based learning (CBL) in the reform practice for integrated curriculum of the digestive system.Methods:The 174 undergraduate students majoring in eight-year clinical medicine enrolled in 2019 at the Peking University Health Science Center were selected as research objects. CBL was used in the integration and optimization of the digestive system curriculum. These included increasing class hours, selecting disease modules, lesson preparation involving multi-disciplinary teachers, and joint teaching. Upon completion of teaching, a comprehensive evaluation of teaching effectiveness was conducted through questionnaires administrated to teachers and students, feedback from supervision experts, and scores of students. SPSS 21.0 was used for the t-test and a reliability analysis was conducted on the questionnaire results. Results:Teachers, students, and supervision experts were highly satisfied with CBL. More than 95% of teachers believed that joint teaching facilitated the sharing of diverse professional knowledge among teachers, enhanced the in-depth instruction of imaging knowledge, promoted the transformation of teaching ideas, and improved teaching ability. More than 70% of students agreed that joint teaching deepened their understanding of diseases, stimulated learning interest, and established a theoretical foundation for clinical practice. The average score of class performance was (47.60±2.41) points (a total score of 50 points). The answers of students to case-based questions in final exams were satisfactory. The average score of final evaluation was (82.24±8.82) points.Conclusions:The optimization and application of CBL in the integrated curriculum of the digestive system is highly accepted by teachers and students. This method improves the interest of learning and facilitates the establishment of overall medical thinking and clinical thinking in students.

Objective:To explore and evaluate the optimization and application of case-based learning (CBL) in the reform practice for integrated curriculum of the digestive system.Methods:The 174 undergraduate students majoring in eight-year clinical medicine enrolled in 2019 at the Peking University Health Science Center were selected as research objects. CBL was used in the integration and optimization of the digestive system curriculum. These included increasing class hours, selecting disease modules, lesson preparation involving multi-disciplinary teachers, and joint teaching. Upon completion of teaching, a comprehensive evaluation of teaching effectiveness was conducted through questionnaires administrated to teachers and students, feedback from supervision experts, and scores of students. SPSS 21.0 was used for the t-test and a reliability analysis was conducted on the questionnaire results. Results:Teachers, students, and supervision experts were highly satisfied with CBL. More than 95% of teachers believed that joint teaching facilitated the sharing of diverse professional knowledge among teachers, enhanced the in-depth instruction of imaging knowledge, promoted the transformation of teaching ideas, and improved teaching ability. More than 70% of students agreed that joint teaching deepened their understanding of diseases, stimulated learning interest, and established a theoretical foundation for clinical practice. The average score of class performance was (47.60±2.41) points (a total score of 50 points). The answers of students to case-based questions in final exams were satisfactory. The average score of final evaluation was (82.24±8.82) points.Conclusions:The optimization and application of CBL in the integrated curriculum of the digestive system is highly accepted by teachers and students. This method improves the interest of learning and facilitates the establishment of overall medical thinking and clinical thinking in students.

Objective:To investigate the endoscopic and pathological characteristics of metachronous early gastric cancer (EGC) after endoscopic submucosal dissection (ESD) for EGC.Methods:Data of 451 consecutive EGC patients treated with ESD at the Department of Gastroenterology, Peking University Third Hospital between 1 January, 2005 and 31 December, 2022 were retrospectively collected, of which 252 patients who met the criteria and had endoscopic follow-up ≥ 1 year were enrolled in the retrospective dynamic cohort. Multivariate Cox regression analysis was used to identify independent risk factors for metachronous EGC after ESD. Pearson's contingency coefficient was applied to analyze endoscopic correlation between the index and metachronous lesions. T-test, χ2 test, and Fisher exact test were used to compare endoscopic pathological features between index and metachronous lesions, the proportion of lesions meeting absolute ESD indication and their maximum diameters between patients undergoing annual vs bi-annual follow-up. Kaplan-Meier analysis assessed the cumulative incidence of metachronous EGC. Results:During a median follow-up of 40 months, 26 patients [10.3% (26/252)] developed metachronous EGC, with a mean interval of 43.9 months. Multivariate Cox regression identified the independent risk factors of index lesions including location in the middle third of the stomach ( HR=3.783, 95% CI: 1.300-11.011, P=0.015), in the anterior wall ( HR=3.934, 95% CI: 1.113-13.904, P=0.033), and the maximum diameter <15 mm ( HR=3.034, 95% CI: 1.074-8.571, P=0.036). Pearson's contingency coefficient showed no significant concordance between index and metachronous lesions for vertical location (C=0.375, P=0.372), horizontal location (C=0.508, P=0.434), gross morphology (C=0.287, P=0.675), or ulcer presence (C=0.194, P=0.313). Compared to index lesions, metachronous lesions were more frequently located on the posterior wall (lesser curvature/greater curvature/anterior wall/posterior wall: 11/2/1/12 VS 96/49/46/61, P=0.031), more often differentiated (differentiated/undifferentiated: 26/0 VS 214/38, P=0.032), and smaller in maximum diameter (8.08±5.99 mm VS 13.95±10.26 mm, t=4.383, P<0.001). No significant differences were observed between patients undergoing annual vs bi-annual follow-up in the proportion of metachronous lesions meeting absolute ESD indication (14/16 VS 9/9, P=0.520) or in maximum diameter (8.11±6.94 mm VS 6.67±4.35 mm, t=-0.275, P=0.535). The cumulative incidence curve of metachronous EGC plateaued after 10 years. Conclusion:Patients with EGC located in the middle third of the stomach, in the anterior wall, or of smaller diameter need intensive endoscopic surveillance after ESD. Posterior wall deserves particular attention during follow-up, with annual endoscopy recommended for at least 10 years post-ESD.

Objective To analyze the clinical,pathological,and endoscopic features of differentiated early gastric cancer,and to study predictors to identify and screen high risk patients with early gastric cancer submucosal infiltration.Methods A total of 172 patients with differentiated early gastric cancer treated by surgical or endoscopic submucosal dissection in our hospital from January 2017 to December 2022 were included,which were divided into the mucosal layer group(144 patients)and submucosal layer group(28 patients)based on postoperative pathology.The clinical,pathological,and white-light endoscopy(WLE)and linked color imaging(LCI)features of the 2 groups were compared.The color difference between the lesion and the surrounding mucosa was evaluated by using the Commission International de L'Eclairage(CIE)L*a*b*system.Indicators with significant differences were included to multifactor logistic stepwise regression analysis(forward method)for the identification and screening of predictors.Results A history of alcohol consumption(P=0.037),a history of smoking(P=0.035),thickening of the gastric wall on enhanced CT(P=0.032),a lesion located in the upper 1/3(P＜0.001)or middle 1/3(P=0.009)part of the stomach,depressed macroscopic type(P＜0.001),marked margin elevation(P=0.003),presence of fold changes(P=0.006),color difference ≥12.3 under WLE(P=0.003)and≥18.2 under LCI(P=0.002)were associated with submucosal infiltration.Multivariate analysis showed that lesions located in the upper 2/3 portion of the stomach(OR=5.463,95％CI:2.562-11.648,P＜0.001),depressed macroscopic type(OR=5.992,95％CI:1.624-22.100,P=0.007),marked margin elevation(OR=4.338,95％CI:1.124-16.747,P=0.033),and color difference ≥18.2 under LCI(OR=4.675,95％CI:1.342-16.288,P=0.015)were independent risk factors for infiltration of submucosal layer of lesions.Conclusion Lesions with depressed macroscopic type,marked elevated margins,located in the upper 2/3 part of the stomach,and having a large color difference from the surrounding mucosa under LCI are high-risk lesions for submucosal infiltration and require more aggressive intervention.

Objective:To evaluate the long-term clinical efficacy of endoscopic submucosal dissection (ESD) in the treatment of early colorectal cancer and precancerous lesions, and to explore the risk factors of local recurrence after operation.Methods:From January 1, 2011 to December 31, 2022, the clinical and endoscopic follow-up data of 1 095 patients (1 186 lesions) who underwent ESD at Peking University Third Hospital and were pathologically diagnosed as early colorectal cancer or precancerous lesions after ESD were retrospectively analyzed. The long-term efficacy of ESD was evaluated, which included 5-year overall survival rate, disease-specific survival rate, local recurrence rate, and recurrence-free survival rate. The Kaplan-Meier method was used for survival analysis. Multivariate Cox proportional hazards regression models were performed to analyze local recurrence related clinical pathological factors.Results:After ESD, 1 067 patients were followed up, and the median follow-up period was 44.4 (20.3, 62.1) months. There were 734 patients having endoscopic follow-up (798 lesions, the follow-up rate was 67.0%). During the follow-up period, 26 patients died, and the 5-year overall survival rate and disease-specific survival rate were 96.0% and 100.0%, respectively. During the follow-up period, local recurrence was observed in 17 lesions, with a recurrence rate of 2.1%(17/798) and a median time of recurrence after ESD was 11.8 (4.9, 21.4) months. The 5-year cumulative recurrence rate was 3.4%, and the 5-year recurrence-free survival rate was 94.0%. The results of multivariate Cox regression analysis showed that lesions located in the rectum ( HR=2.64, 95% confidence interval (95% CI) 1.00 to 6.94, P=0.049), histologically incomplete resection ( HR = 4.40, 95% CI 1.62 to 11.94, P=0.004), and positive vertical margin ( HR=10.27, 95% CI 2.95 to 35.77, P<0.001) were independent risk factors for local recurrence after ESD in the treatment of colorectal mucosal lesions. Conclusions:Long-term efficacy of ESD in the treatment of colorectal mucosal lesions are favorable. Lesions located in the rectum, histologically incomplete resection, and positive vertical margin are independent risk factors for local recurrence after ESD in the treatment of colorectal mucosal lesions.

Helicobacter pylori (Hp) infection is one of the main causes of gastric cancer. The virulence factors of Hp, cytotoxin⁃associated gene A (CagA) and vacuolating cytotoxin A (VacA), are closely related to the pathogenicity of Hp in European and American countries. However, the positivity rate of CagA is as high as 90% in East Asian countries, indicating that the above⁃mentioned virulence factors could not fully explain the differences in pathogenicity of Hp, and other pathogenic factors might be speculated. In our previous studies, thioredoxin⁃1 (Trx1) was found to be a virulence factor of highly pathogenic Hp, and a series of studies were conducted on Hp Trx1 in cytology, zoology and human histology. This article reviewed the progress in research on Hp Trx1.

Background:Cronkhite Canada syndrome(CCS)is a rare non hereditary disease of unknown etiology,there are still challenges in its diagnosis and treatment.Aims:To explore the clinical characteristics and treatment responses of CCS in Chinese population,and to improve the understanding of its diagnosis and treatment.Method:Retrospective analysis and summary of clinical data of CCS patients at Peking University Third Hospital from 2012 to 2022.Results:From the clinical data of a total of 9 cases,the patients'average age was 63.89 years,and the male to female ratio was 1.25.all patients presented with multiple gastrointestinal polyps,non-specific gastrointestinal symptoms and at least one ectodermal manifestation.Laboratory tests for fecal occult blood were positive,and iron deficiency anemia and hypoalbuminemia were common.Histological manifestations were hyperplastic polyps and adenomatous polyps,with commonly found eosinophil infiltration.Patients'conditions could be complicated with severe osteoporosis and fractures,intestinal bacterial overgrowth,asthma,membranous nephropathy,and nodular goiter.Most patients obtained positive currative effect with glucocorticoids therapy,but recurrence of the disease may occur during or after hormone reduction.Azathioprine treatment was attempted in one patient,but the effect was poor.Conclusions:The etiology and pathogenesis of CCS are unclear,and glucocorticoids therapy is still the main treatment method.However,there are still challenges for patients with glucocorticoids resistance and contraindications to glucocorticoids therapy.