Abstract: Objective To establish a highly liver metastatic model of human gastric carcinoma in nude mice by using orthotopic organ selection of metastasis. Methods Histologically intact MKN-45 human gastric carcinoma tissues were orthotopicly implanted into the gastric mucosa layers in nude mice,repeated screening was conducted according to the method of gastric orthotopic implantation→liver metastasis→subcutaneously inoculation→gastric orthotopic implantation. Tumorgenicity, invasion, me-tastasis and morphological characteristics of the implanted tumors were studied by light microscopy and electron microscopy. Results Highly liver metastatic models of human gastric carcinoma named MKN-45sci were obtained after organ screen. They had been passaged in vivo for 5 generations. 100% tumor take rates were observed, the metastases of liver and lymph nodes were noted in all of the animals. They were also exhibited other features： metastasis of lung、spleen、diaphragm and bloody ascites. The primary and metastatic tumors were similar to the original human carcinoma in histopathological and electron microscopy features. Conclusions The orthotopic implant models of human gastric carcinoma displayed features of human clinical gastric carcinoma in animals. They provided a useful tool for the study of metastatic mechanism and treatment of human gastric carcinoma.

Key words: Nude mice, Human gastric carcinoma, Metastasis, Disease model