Background: Vitamins are nutrients essential for human health. They act as coenzymes that help trigger important chemical reactions necessary for energy production. Reference values for vitamins help physicians evaluate the health status of patients and make clinical decisions. The aim of this study was to determine the mean values and reference intervals for some water-soluble vitamins of Mongolian adults. Materials and Methods: Three hundred and forty healthy adults (170 males and 170 females) of 17 to 69 years of age were selected for the study based on CLSI C28-P3 criteria Defining, establishing & Verifying reference interval in the clinical laboratory; Proposed Guidelines. The study was approved by the Resolution No.76 of 2018 of the Medical Ethics Review Committee of the Ministry of Health. Informed consents were taken from the selected individuals. Morning blood samples of the participants were collected under aseptic conditions. Levels of vitamins B₆, B₉, B₁₂ and vitamin C were measured using a high performance liquid chromatography method. The lower- and upper reference limits were defined as the 2.5th and 97.5th percentiles, respectively. The data were analyzed using SPSS and Excel programs. Results: The mean blood level of vitamin C was 11.88 mg/L (95% CI 10.47-13.29) for men and 9.62 mg/L (95% CI 8.11-11.13) for women. The calculated reference interval for males was 1.40-19.40 mg/L and 1.17-18.04 mg/L for females. The mean concentration of vitamin B₁₂ in the blood of males was 938.45 ng/L (95% CI 747.22-1129.68) and that of females was 864.03 ng/L (95% CI 603.81-1124.25). The reference interval for vitamin B₁₂ was 233.03-1597.00 ng/L in men and 132.45-1623.86 ng/L in women. The mean level of vitamin B₉ was 8.47 ng/mL (95% CI 5.64-11.30) for men and 6.91 ng/mL (95% CI 4.89-8.93) for women. The calculated reference interval for this vitamin in males was 1.04-24.74 ng/mL and that in females was 1.04-21.46 ng/mL. As for vitamin B₆, the mean concentration for men was 44.42 ng/mL (95% CI 37.01-51.83) and for women was 34.67 ng/mL (95% CI 29.97-39.39) with the reference intervals of 5.90-79.02 ng/mL for men and 5.27-61.72 ng/mL for women. Conclusion The reference values for vitamins B₆, B₉, B₁₂ and vitamin C of Mongolian adults do not differ significantly from those observed in other populations. The calculated reference intervals can be used in the practice of health laboratories.

Background: Currently, colorectal cancer (CRC) ranks as the third most common cancer and the second leading cause of cancer-related mortality worldwide. CRC frequently metastasizes to the liver (50%), lungs (10–15%), peritoneum (4%), bones (10.7%–23.7%), brain (0.3%–6%), and spinal cord. Approximately 35% of CRC cases are diagnosed before distant metastasis, 36% upon lymph node involvement, and 23% after distant organ metastasis. Although several studies have established primary tumor models in mice in our country, there are limited studies on experimental lung metastasis models, prompting the need for this research. Aim: To establish and evaluate a lung metastasis model of colorectal cancer in C57BL/6J mice using the MC38 cell line. Materials and Methods: This study was conducted at the Institute of Biomedical Sciences, Mongolian National Uni versity of Medical Sciences. Approval was obtained from the Ethics Review Board of the Mongolian National Univer sity of Medical Sciences (2023/3-09) and all laboratory safety regulations and protocols were strictly followed. Male C57BL/6J mice bred at the Experimental Animal Center of Mongolian National University of Medical Sciences were used. MC38 murine colorectal carcinoma cells were cultured and injected intravenously (via the tail vein) at a concen tration of 0.25×10⁶ cells per mouse (n=12) to induce lung metastasis. Histological analysis was subsequently performed. Results: Histological examination revealed significant alterations in lung tissue architecture, characterized by areas of dense infiltration by pleomorphic, hyperchromatic cells, disrupting the normal alveolar structure. No histological abnor malities were observed in other organs. Conclusion Intravenous injection of MC38 colorectal adenocarcinoma cells into the tail vein of C57BL/6J mice success fully induced lung metastases, characterized by hyperchromatic, pleomorphic cell infiltrates forming glandular structures within the lung parenchyma.