AGS cell line xenograft tumor as a suitable gastric adenocarcinoma model: growth kinetic characterization and immunohistochemistry analysis

OBJECTIVE(S): Gastric cancer is the third leading cause of cancer-related death worldwide. The overall survival rate of patients is poor because gastric cancers are usually diagnosed at the late stages. Therefore, further research is needed and appropriate research tools are required to develop novel therapeutic approaches. MATERIALS AND METHODS: Eight female athymic nude mice with a C57BL/6 background were used in this study. AGS cells were inoculated into the flank. The tumor volumes were calculated and growth curves were drawn. When the volume of the tumors reached 1000 mm3, the animals were humanely euthanized with CO(2) gas. After harvesting, tumors were analyzed with Hematoxylin and Eosin (H&E) and immunohistochemistry (IHC). A pathologist confirmed tumor entity through H&E staining. Tumors were evaluated for expression of HER-2, P53, Ki-67, CD34, cytokeratin 8 (CK8), vimentin, estrogen receptor (ER), and progesterone receptor (PR) utilizing immunohistochemistry. RESULTS: The tumor take rate was 62.5%, mean doubling time was 40.984 d, and the latency period was 30.62 days. The H&E staining results showed highly malignant hyperchromatin epithelial cells. IHC assessment showed the mutation status of P53 gene. The expression score of the CK8 protein in the tumor cells was +3. Vimentin protein was not expressed and changes in mesenchymal phenotype were not observed. Ki-67 IHC indicated that the proliferation rate was >43% and angiogenesis was defined as high MVD. CONCLUSION: The respective AGS xenograft model provides an opportunity to understand the pattern of tumor growth as well as to evaluate new gastric cancer therapies in in vivo studies.