To analyze the human gastric carcinoma metastasis to the liver, a human gastric carcinoma line, AZ521 was injected into the spleens of nude mice. Cells from the few liver metastatic foci of injected AZ521 were expanded in vitro and subsequently injected into the spleens of nude mice. By repeating these proce-dures five times, we were able to obtain a cell line, designated AZ-H5c, with high metastatic potential in nude mice. It was observed that animals had liver metastasis in 10 of 12 (83%) cases injected with AZ-H5c, whereas only 14% with parental AZ521. The growth activity in vivo of AZ-H5c cells is much more rapid than that of AZ521 cells, but its growth activity in vitro is slower. The mortile activity in vitro of AZ-H5c is stronger than that of AZ521. These results suggest that our model can provide a new approach to basic and clinical studies of cancer metastasis
