Background: CagA (cytotoxin-associated gene A protein) is an oncoprotein produced by Helicobacter pylori, a bacterium implicated in gastric carcinogenesis. CagA has been identified in all H. pylori strains isolated from patients with gastric cancer. To date, comparative studies investigating the genetic diversity of the cagA gene at the international level remain limited, and its pathogenic mechanisms have not yet been fully elucidated. Aim: To characterize the global and regional diversity of the cagA gene in H. pylori, and to evaluate the relationship of its prevalence and genotypic variants with gastric cancer. Materials and Methods: This molecular epidemiological study analyzed 9,276 H. pylori genomes from human hosts across 93 countries that were publicly available in international databases as of November 2024, together with 300 newly generated whole-genome sequences of H. pylori isolates from the Mongolian population that had not previously been deposited in public databases. To determine the genetic diversity of this oncogene, comprehensive genome bioinformatics analyses were performed, including genomic, phylogenetic, genotypic, and in silico protein analyses. Result: After quality control, 7,150 H. pylori genomes were included in the final analysis. Overall, 80.9% (n=5,783) of H. pylori strains were found to harbor the cagA gene, with the highest prevalence observed in Asia and the lowest in Europe. Maximum-likelihood phylogenetic analysis revealed substantial genotypic diversity of cagA and marked geographic variation in its distribution. Specifically, five distinct CagA protein types were identified, two of which represented previously undescribed novel types. The distribution of CagA types was found to correlate more strongly with the incidence of gastric cancer than the mere presence of cagA-positive H. pylori. Conclusion The majority of H. pylori strains in human populations worldwide harbor the CagA oncoprotein, with an overall prevalence of approximately 81%. Differences among CagA types may contribute to regional variation in gastric cancer risk. The diversification and evolutionary changes of the cagA gene may reflect recent processes of genetic admixture, which in turn shape its geographic and ethnic distribution as well as its pathogenic potential.

Background: According to the 2024 national health statistics of Mongolia, colorectal cancer accounts for 5.1% of all newly diagnosed cancers, with 74.1% detected at an advanced stage. Although population-based screening programs have recently been implemented, no studies have established a risk factor–based scoring system with an optimal cut-off value or evaluated its clinical utility in resource-limited settings in Mongolia. Aim: To develop a modified APCS (mAPCS) scoring system and evaluate its clinical applicability for colorectal cancer screening. Materials and Methods: A hospital-based prospective cross-sectional study was conducted between December 2024 and February 2026 at the outpatient clinics of the Mongolian National University of Medical Sciences and the Mongolia–Japan Hospital. A total of 447 eligible participants were enrolled. Anthropometric measurements (height and weight) were obtained, and six categories of questionnaires (demographic data, APCS risk score, behavioral factors, medical history, and medication use) were administered. Eleven participants declined colonoscopy; therefore, 436 participants underwent colonoscopic examination, with histopathological evaluation performed when indicated. Results: A total of 436 participants were included, of whom 282 (64.7%) were female, with a mean age of 54.8±11.5 years. Colorectal adenomas (advanced and non-advanced) and colorectal cancer were detected in 199 (45.6%) participants. Among them, 43 (21.6%) had advanced colorectal neoplasia. Multivariable regression analysis identified age ≥55 years (OR 4.8), BMI ≥28 kg/m² (OR 3.6), and a family history of colorectal cancer (OR 3.1) as independent risk factors for advanced neoplasia. The optimal cut-off value for the mAPCS score was 4, with an overall diagnostic accuracy of 41.7% (sensitivity 97.7%, specificity 35.6%). Conclusions 1. Age ≥55 years, BMI ≥28 kg/m², and a family history of colorectal cancer were identified as independent risk factors for advanced colorectal neoplasia. At a cut-off value of ≥4, the mAPCS scoring system demonstrated high sensitivity (97.7%), low specificity (35.6%), high negative predictive value (99.2%), and low positive predictive value (14.2%). 2. Therefore, the mAPCS scoring system may serve as a useful tool for risk stratification and efficient allocation of limited resources in colorectal cancer screening.

Background: Inflammatory bowel disease (IBD) is a chronic immune-related condition caused by interactions between genetics, immune dysfunction, gut microbiota changes, and environmental factors, often presenting as persistent or recurring diarrhea. Clinically, it commonly presents with chronic diarrhea and other gastrointestinal symptoms. The global prevalence of IBD is increasing, currently affecting approximately 0.5% of the population, with projections suggesting a rise to nearly 1% by 2030. Fecal calprotectin is a neutrophil-derived S100 calcium-binding protein that is elevated in intestinal mucosal inflammation and serves as a reliable noninvasive biomarker of inflammatory activity. Due to its high stability and close association with intestinal inflammatory activity, fecal calprotectin has been established as a dependable, non-invasive marker for identifying intestinal inflammation. In clinical practice, it is extensively used to distinguish IBD from functional gastrointestinal disorders, especially irritable bowel syndrome, among patients presenting with chronic diarrhea. However, its diagnostic utility in Mongolia remains underexplored, and this study aims to determine its sensitivity and specificity in inflammatory bowel disease and compare its diagnostic performance with other inflammatory markers. Aim: To determine the sensitivity and specificity of fecal calprotectin in inflammatory bowel disease and to compare it with other inflammatory markers. Materials and Methods: A total of 109 participants aged 18-87 years with chronic diarrhea, who attended the gastroenterology outpatient clinics of the Mongolia–Japan Hospital and Intermed Hospital between December 2024 and December 2025 and provided informed consent, were enrolled in this study. Data were collected using structured questionnaires, and laboratory investigations included complete blood count, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and measurement of fecal calprotectin levels from stool samples. Based on fecal calprotectin results, selected participants underwent colonoscopic examination as clinically indicated. Results: Among the 109 participants included in the study, 17.4% were diagnosed with inflammatory bowel disease (IBD), with a mean age of 47.41±15.52 years. Fecal calprotectin levels were significantly higher in the IBD group compared to the control group (p<0.001). Fecal calprotectin demonstrated a weak positive correlation with C-reactive protein (CRP) and leukocyte count (p=0.042, p=0.06), while no significant correlation was observed with erythrocyte sedimentation rate (ESR). At a cutoff value of 250 µg/g, fecal calprotectin showed a sensitivity of 94.4%, specificity of 69.2%, positive predictive value (PPV) of 37.8%, and negative predictive value (NPV) of 98.4%. Receiver operating characteristic (ROC) curve analysis identified an optimal cutoff value of approximately 400 µg/g (AUC=0.919, Youden index=0.724), at which the sensitivity remained 94.4% and specificity increased to 78.0%. In contrast, CRP and ESR demonstrated comparatively lower diagnostic performance, with AUC values of 0.640 and 0.644, respectively. Conclusion This study demonstrates that fecal calprotectin has superior diagnostic performance compared to conventional inflammatory markers in differentiating inflammatory bowel disease (IBD). An optimal cutoff value of approximately 400 µg/g yielded the highest sensitivity and specificity. Therefore, fecal calprotectin may serve as a valuable tool in clinical practice for both screening and diagnostic confirmation.

Background: The intestinal microbiota of Mongolians and its composition is of great interest of researchers, a few studies have did in this fields. Maybe Mongolian encompass a uniquely wide range of environmental conditions, ethno geographical cohorts and traditional nomadic lifestyles. Goal: We aimed to determine the amount of gut microbiota, including Lactobacillus and Bifidobacterium in the fecal samples of relative healthy Mongolian adults residing in various regions of Mongolia by conventional culture method and PCR. Material and Methods: The study was performed population based cross sectional study in healthy volunteers. In this study, 256 relative healthy Mongolian adults with no history of gastrointestinal associated diseases were enrolled between July 2018 and April 2019. Each participants was asked to complete a questionnaire containing 164 questions about demographics, physical activity, dietary habits. Fecal samples were collected for Lactobacillus and Bifidobacterium analysis using culture method and determination of genus of Bifidobacterium sрp and Lactobacillus spp by PCR. ResultsParticipants had a mean age of 38.9±12.8 years. The mean values of Lactobacillus by culture method were 5.9±1.28 and 6.24±0.94 log10 CFU/ml (4.67х106 , 4.66х106 CFU/ml), respectively. The abundance of Lactobacillus had a positive correlation with grams for fiber and amount of bifidobacterium ((r= 0.495, р<0.001, r=0.288, p<0.05), respectively). Significant difference were observed between groups of milk frequency per day for amounts of lactobacillus. In adult intestinal tracts, B.Bifidum was the most common taxon 31 (29%) followed by B. angulatum 14 (13.1%), B. adolescentis 10 (9.3%), B. catenulatum group 10 (9.3%), B. longum 9 (8.4%). B. lactis, B. breve, B. dentium and B. gallicum were subdominant species. Conclusion: The mean amount of Bifidobacterium and Lactobacillus of all participants were 6.24±0.94 and 5.9±1.28 log10 CFU/ml (4.66*106 , 4.67*106 CFU/ml) respectively. The Lactobacillus abundance of healthy adults was higher in region of Khangai, East and West of Mongolian than other regions. The composition of lactobacillus altered with ageing. Significant correlations were found between fiber, fats, potato and amount of Lactobacillus. Keywords: Bifidobacterium, Colony forming unit, Gut microbiota, Lactobacillus

Introduction: Coronary atherosclerosis is the leading cause of morbidity and mortality in the world. Hypogonadism is not considered a traditional risk factor for coronary artery disease (CAD). Higher CVD mortality may be partially attributed to behavioral and physical characteristics of males, including increased smoking, drinking, endocrine and metabolic factor like fat distribution, and low male engagement in preventive care. In the last decades, many studies have suggested that low testosterone levels are associated with increased prevalence of risk factors for CVD, including dyslipidemia and diabetes. For the reason, this research focused on identifying any association between testosterone deficiency and risk factors of coronary heart disease. Goal: This study aimed to identify any association between testosterone deficiency and risk factors of coronary heart disease in Mongolian men. Material and methods: In this case control study, we determined plasma total testosterone, total cholesterol, triglyceride, high density lipoprotein-cholesterol, apolipoprotein – ApoA1, Apo B and glucose in 287 subjects, among them 125 patients with ACS and 162 healthy subjects. Statistical analysis was performed using SPSS 22.0 of IBM. Results: Mean age of the participants was 55.19±6.99 years old. It was found that, mean plasma TT levels in patients with ACS (4.17 ng/ml) was significantly lower than in the healthy subjects (4.70 ng/ml). There was a negative association between plasma TT level and glucose level (r=-0.185; p=0.002) and ApoB/ApoA1 (r=-0.132, p=0.026). Conclusion The results in the present study suggest that low plasma TT level may be a risk factor for CHD in men, which may relate to the influence of plasma lipoprotein and glucose metabolism by endogenous testosterone.