Background: Lung cancer remains the leading cause of cancer-related mortality worldwide, accounting for approximately 1.8 million deaths annually and representing 18% of all cancer deaths¹. According to the GLOBOCAN 2024 report, 2.4 million new cases were registered globally, ranking second after breast cancer². Non-small cell lung cancer (NSCLC) constitutes 85% of lung cancer cases, with adenocarcinoma being the most common subtype³. The objective of this study is to map the prevalence of HER2 activation and mutations in EGFR, EML4-ALK, ROS1, BRAF, and KRAS genes among lung cancer patients in Mongolia, and to evaluate their correlations with clinical and morphological parameters (age, sex, smoking status, stage, and morphology). Aim: To determine the distribution pattern of HER2 activation and EGFR, EML-ALK, ROS1, BRAF, KRAS gene mutations among patients with lung cancer in Mongolia, and to evaluate their associations with clinical and morphological characteristics. Materials and Methods: A retrospective study was conducted using archived materials from lung cancer patients at the Clinical Pathology, Molecular Genetics, and Pathology Laboratories of the National Cancer Center of Mongolia, covering the period from 2019 to June 2025. DNA Extraction from Tumor Tissue: Formalin-fixed paraffin-embedded (FFPE) tissue blocks from patients diagnosed with lung cancer, stored in the pathology department archives, were selected for the study. Sections of 5–10 μm thickness were cut, mounted on glass slides, stained with hematoxylin and eosin (H&E), and reviewed by a pathologist. Areas containing ≥20–30% tumor cells were identified and macro-dissected for analysis. Real-Time PCR Assay for Detection of EGFR/BRAF/KRAS/EML4-ALK/ROS1 Mutations: EGFR mutation detection was performed using the PANAMutyper™ EGFR Mutation Detection Kit (Panagene, Daejeon, South Korea) according to the manufacturer’s instructions. PCR reactions were carried out on a compatible instrument (Roche LightCycler 480, Germany) as recommended by the manufacturer. Statistical analysis was performed using Prisma-10 software. Results: A total of 282 lung cancer cases were included in the study. EGFR mutations were detected in 44% of cases and were absent in 56%. No significant age-related differences were observed (p=0.2636); however, EGFR mutations were significantly more frequent in females (36.6% vs. 19.6%, p=0.0019). No statistically significant differences were found across disease stage, T, N, or M classifications (p>0.05). No association was identified between smoking status and EGFR mutations (p=0.4178). Morphologically, EGFR mutations were significantly more prevalent in adenocarcinoma (54.83%) compared to squamous cell carcinoma (SCC) (31.8%; p=0.002). Of the 282 cases, adenocarcinoma accounted for 155 (54.9%) and SCC for 116 (41.1%). Overall, EGFR mutations were positive in 43.97% of cases, with a higher prevalence in adenocarcinoma (24.82%) than in SCC (13.1%). By exon: - Exon 18 mutations were detected in 6% of cases, predominantly in adenocarcinoma (6%, 4.25%). - Exon 19 mutations occurred in 8.15% and are associated with sensitivity to targeted therapy. - Exon 20 mutations were found in 3.19%, with the T790M resistance variant in 1.77%. - Exon 21 mutations were observed in 9.57%, more common in adenocarcinoma (9.57%) than in SCC (3.19%). Survival analysis stratified by stage at diagnosis showed significantly longer median survival in early-stage patients (18.6 months). Kaplan-Meier curve comparison, log-rank test, and hazard ratio calculations confirmed statistically significant differences (p < 0.05), indicating that disease stage is a key prognostic factor. Conclusion The study findings reveal a high prevalence of EGFR mutations among Mongolian patients with lung adenocarcinoma, underscoring the need for widespread implementation of targeted therapy (EGFR-TKIs). In contrast, mutation rates were lower in SCC and other morphological subtypes, highlighting the importance of investigating alternative molecular markers in these subgroups.

Background: Globally, gastric cancer accounts for 1,089,000 new cases and 769,000 deaths annually, ranking fifth in overall cancer incidence and third in cancer-related mortality. The aim to determine HER2 expression in patients with gastric cancer and to evaluate its correlation with clinical and immunological biomarkers, as well as the need for further laboratory diagnostics. Aim: To determine HER2 expression in patients with gastric cancer and to evaluate its association with clinical and immunological biomarkers, as well as the potential need for further laboratory diagnostics. Materials and Methods: A retrospective study was conducted using archived materials from patients with gastric cancer at the Clinical Pathology, Molecular Genetics, and Pathology Laboratories of the National Cancer Center of Mongolia, covering the period from 2019 to June 2025. HER2 protein expression in tumor tissue was assessed using immunohistochemistry (IHC), and chromogenic in situ hybridization (CISH-HER2) was employed to confirm gene amplification. Statistical analysis was performed using the Prisma-10 software. Results: In our study, among 210 cases of gastric cancer evaluated by IHC for HER2, 46 (21.9%) were HER2-positive and 164 (78.1%) were HER2-negative. When comparing patients with gastric cancer stratified into HER2 1+ (negative) and HER2 3+ (positive) groups, no statistically significant differences (p < 0.05) were observed in age, sex, tumor location (surgically resected tissue), morphology, or disease stage. However, a higher proportion of males was noted in the HER2 3+ group (80.9%), though this did not reach statistical significance (p = 0.0879). Significant associations were found with tumor markers. Elevated serum CA-72-4 (>5 ng/mL) was more frequent in the HER2 3+ group (58.8%; p = 0.0069). In contrast, elevated CA-19-9 (>35 U/mL) was more common in the HER2 1+ group (93.5%; p = 0.0117), and elevated CEA (>6.9 U/mL) was also predominant in the HER2 1+ group (90.6%; p = 0.002). These findings suggest that HER2 3+ status predominates in cases with elevated CA-72-4, which may influence diagnostic strategies and HER2-targeted therapies (e.g., trastuzumab). Conversely, elevated CA-19-9 and CEA were more associated with HER2 1+ status, indicating a need for further detailed investigation of these markers in relation to HER2 expression. In patients evaluated by CISH for HER2 expression, stratification into HER2-positive and HER2-negative groups revealed no statistically significant differences (p < 0.05) in age, sex, tumor location, morphology, stage, or serum tumor markers (CA-72-4, CA-19-9, CEA). This suggests that HER2 status (positive/negative) may be independent of these variables. Although HER2 positivity was higher in poorly differentiated tumors (48% vs. 30.6% negative; p=0.1414) and in stage IV disease (50% vs. 39.3% negative; p=0.2607), these differences were not statistically significant. Elevated serum markers (CA-72-4, CA-19-9, CEA) were observed but showed no significant correlation with HER2 status. Conclusion Determining the molecular profile of gastric cancer patients can significantly contribute to refining clinical diagnosis, developing treatment strategies, enhancing therapeutic outcomes, and improving patients’ quality of life.

Background: Infectious keratitis is a disease caused by inflammation, infection, and other ocular damage to the outer and other deep layers of corneal epithelium. It is a major cause of monocular blindness and visual disability worldwide regardless of age and gender. Therefore, we aimed to determine the clinical features and risk factors of infectious keratitis among Mongolians and to identify the causative microorganism and compared them with the treatment results. Methods: We collected the data of 149 patients who diagnosed as infectious keratitis at the Ophthalmology Department of the First State Central Hospital in 2017-2020 and using a case series model of descriptive study. Statistical analysis was calculated using Stata14 software. Results: The majority of patients in our study were male, with a male-to-female ratio is 2.1:1. The cause of infectious keratitis were categorized and eye injury-induced keratitis accounted for the highest percentage of 38.3% (n=57), with the majority being men 73.7% (n=42) (p=0.028). As for the type of treatment, antibacterial drugs 103 (69.1%) and evisceration 27(45%) predominate. Conclusion Our study shows that the majority of infectious keratitis in Mongolia is due to trauma in male patients. Forty-five percent of all surgeries involve evisceration surgery, which reduces the client's quality of life.

BACKGROUND: There are two general types of age-related macular degeneration: dry and wet. During wet or neovascular age-related macular degeneration new abnormal vessels grow and leak in the macula. As anti-vascular endothelial growth factor (anti-VEGF) was invented, it revolutionized the treatment of nAMD by inhibiting the progress of this disease. The incidence of AMD increases as life expectancy grows and there is a growing need to study this disease. We aimed to evaluate the outcome of anti-VEGF therapy for the treatment of nAMD and the incidence of ocular serious adverse events (SAE) after injections.. METHODS: In our retrospective, single-center study, medical records of patients receiving a single dose of anti-VEGF treatment (Bevacizumab) for nAMD between 17th of April, 2016 and October, 2017 were evaluated. Outcome measures were the change in the baseline visual acuity (VA) score at post-injective month one, incidence of ocular SAE and patients’ baseline characteristics affecting VA. Patients, whose treatment were started before April 2016 and had anti-VEGF treatment for the diseases other than nAMD, were excluded.. RESULTS: 15 eyes in 15 patients between 52 and 85 years of age received single dose of anti-VEGF (Bevacizumab/Avastin) injection. The mean baseline VA improved from pre-injective average of 0.21 to post-injective 1-month average of 0.37 by Snellen. Furthermore, there was no vision loss or other severe adverse effects, such as endophthalmitis, vitreous hemorrhage, retinal detachment, traumatic cataract after 4 weeks. CONCLUSION: Anti-vascular endothelial growth factor therapy has promising short-term outcomes on treating neovascular age-related macular degeneration.

BACKGROUND: Pterygium is a fibrovascular wing shaped encroachment of conjunctiva onto the cornea. Although the pathogenesis remains obscure, the ultraviolet radiations (UVR), especially UVR-A and UVR-B (290-400 nm), are considered the most dangerous in developing pterygium among other environmental factors (hot, dry, windy, dusty and smoky environments and hereditary factors. The main histopathological change in primary pterygium is elastotic degeneration of conjunctival collagen. Patient complaints include foreign body feeling and visual loss due to corneal astigmatism or growth over the pupil and cosmetic problems. Anti-inflammatory drugs and lubricants have an important role minimizing the patient’s discomfort, but they do not cure the disease. After surgical removal there are still many recurrences regardless of the method used. Autologous conjunctival grafting seems to be the best method, given both the low recurrence rate and high safety. As described first by Kenyon et al. in 1985, a conjunctival autograft reported a recurrence rate of 5.3% with infrequent and relatively minor complications. The primary disadvantage of this technique is the prolonged operative time required when compared to the bare sclera technique. These disadvantages are outweighed by the lack of sight-threatening complications and the relatively low recurrence rate, which made this procedure gain popularity in many centers. The application of intraoperative 0.02% mitomycin C for the 5 minutes is efficient in reducing the recurrence rate to a minimum. METHODS: This retrospective case series, single center study was conducted on 239 patients, who underwent pterygium excision from Jan 2017 to Dec 2017 at the Department of Ophthalmology of the First Central Hospital. All patients had a detailed ophthalmic examination before the surgical intervention. Data were collected through a prepared questionnaire. Postoperative follow-up examination sheets were evaluated. Data for recurrence rate of pterygium excision were collected and analyzed by using SPSS version 17.. RESULTS: Among the 239 patients, who underwent an operation, 37.2% (n=89) were male and 62.8% (n=150) were female. Participants’ age ranged from 29 -70 years with mean age of 49.5 years old. There is no statistical significance between the stages of the disease and its post-operative outcome in the patients, who underwent pterygium excision surgery in 2017. Postoperative pterygium recurrence was in 9 patients (3.8%); 5 (55.5%) out of all 9 patients with recurred pterygium had underwent pterygium excision without conjunctival autograft. MMC was not used intraoperatively for all 9 (3.8%) patients with recurrence post pterygium excision. CONCLUSION: The relationship between pterygium stage and its post-operative recurrence was not statistically significant (P=0.683). The recurrence rate after pterygium excision with conjunctival autograft was low (P≤0.001) which showed significant statistically. There was no recurrence after pterygium excision with MMC (P≤0.001). The results of studies from Canada, Hong-Kong, India, Philippines and Iran were similar to our outcome.

Эвэрлэгийн цагаа, эвэрлэгийн бусад эмгэгийн үед төгс эмчилгээний арга нь эвэрлэг шилжүүлэн суулгах юм. Deep Anterior lamellar keratoplasty (DALK) мэс засал нь гэмтсэн эвэрлэгийн стромын давхарга болон эпителийг бүхэлд нь аван эрүүл эндотели болон десцемет давхаргыг нь үлдээн хийдэг хагалгаа юм. DALK мэс заслын үед Мухамед Анварын том бөмбөлгөн (“Big Bubble” technique) техникийг дэлхий дахинд өргөн ашигладаг ба үүнийг өөрөөр десцеметийн давхаргыг ил гаргах техник (Descemet’s baring technique) гэж нэрлэдэг. Энэ техникийн үед агаарыг эвэрлэгийн стромлуу шахаж өгдөг ба тухайн шахсан агаар нь стромыг десцеметийн давхаргаас салган гэмтсэн эдүүдийг эрүүл эдээс тусгаарлана. Сүүлийн хэдэн жил том бөмбөлгөн техникээр Deep Anterior lamellar keratoplasty (DALK) хагалгааг олон удаа хийх явцад Дуа-гийн давхаргыг олж нээсэн. Энэхүү судалгаанд Дуа-гийн давхаргын онцлог шинж чанар, анатомийн байрлал, түүний нотолгоо болон эмнэл зүйн ач холбогдол хэрэглээг судалсан.

INTRODUCTION:According to the report from 2010, Mongolian water consumption was 550 million cubic meter andapproximately 9.1% of the total Mongolian population obtain their water from inadequate hygiene waterresources - springs and rivers. Due to non-hygiene water usage has caused water-born communicableand non communicable diseases among the population. In the last years there has been issue of pollutionof one of the Mongolia’s more representative river Selenge and its following rivers -Kharaa, Orkhon andit is necessary to evaluate water pollution of these rivers.GOAL:To determine water chemical and biological pollution of Kharaa and Orkhon river and to evaluate waterqualityMaterials and MethodsWe collected water, sediments and macro invertebrates sample from three points of river -upstream,midstream, downstream and for Kharaa river the samples were collected from Tunkhel, Mandal andBayangol soum, fo Orkhon river the sequence was Orkhontuul, Orkhon, Khushaat soum. Samples werecollected June, August, October of 2011, 2013.In water sample, we determined physic-chemical 15 parameters including temperature, pH, total dissolvedsolids, conductivity, smell, color, hardness, sulfate, chloride, nitrate, nitrite, ammonia, dissolved oxygen,biological oxygen demand and mercury using their standard methods. Macro invertebrate samples werecollected to evaluate water quality and we determined mercury in sediments and macroinvertebratesamples to evaluate mercury contamination.RESULT:Physic-chemical results of the water showed that water of Kharaa, Orkhon rivers were classified lowmineralized, soft water and nutrient pollution indicators for ‘slightly polluted’category. For dissolved andbiochemical oxygen, they were belong to the category of ‘pure water’.There were no correlation between 2012 and 2013 results and mercury in water, sediments and macroinvertebrates were qualified standard value.CONCLUSION:According to research results water quality of Kharaa, Orkhon river was good and have less pollution andit is possible to use in household consumption after proper cleaning and disinfection.