Manifestation of metastatic potential in human gastric cancer implanted into the stomach wall of nude mice.

The biological properties of human gastric cancer cell line G/F implanted into either the subcutis or the stomach wall of nude mice were compared. The G/F tumor in the stomach wall showed a slower growth rate than that in the subcutis. The level of carcinoembryonic antigen in serum was greater when the tumor was in the stomach wall than when it was in the subcutis. The tumor in the stomach wall invaded the surrounding tissues and metastasized to the regional lymph nodes and distant organs such as the lung and the liver in 27 of the 43 mice (68%). In contrast, the tumor in the subcutis was highly encapsulated and metastasis to other organs was not observed. These findings indicate that the stomach wall might provide a suitable microenvironment for G/F gastric cancer to exert its intrinsic properties. Therefore, implantation of human gastric cancer into the stomach wall of nude mice may provide a useful model to study the intrinsic characteristics of human cancer as well as the effectiveness of experimental chemotherapy.