Angiogenesis inhibitors have attracted considerable interest. The anti-tumor and anti-metastatic effects of TNP-470, an angiogenesis inhibitor, and mitomycin C (MMC), a representative anti-neoplastic agent, were investigated using a xenotransplanted human colon cancer, TK-4. Suturing of small pieces of TK-4 tumors to the cecal wall in nude mice (orthotopic transplantation) induced liver metastasis. Mice were randomly divided into 3 groups; a control group given saline solution, a group receiving TNP-470 and a group receiving MMC. TNP-470 was given s.c. on alternate days for 5 weeks from day 10 after cecal transplantation and MMC was administered intraperitoneally (i.p.) once a week from day 10 after cecal transplantation. MMC significantly inhibited cecal tumor growth. In the control group, liver metastases developed in 9 out of 10 mice, including 3 with more than 20 metastatic foci. Liver metastasis also developed in 8 out of 10 mice receiving MMC, 2 of which had many metastases. In contrast, liver metastasis developed in only 2 out of 8 mice in the TNP-470 group and neither of these animals had numerous metastases.