[Metastatic behavior of footpad-inoculated tumors in mice and the impact of OK-432 per os administration].

In the surgical treatment of cancer patients, it is very important to investigate the immunological potential of regional lymph nodes. The purpose of this study was to clarify the defence mechanisms of regional lymph nodes against cancer cell dissemination. The materials used for the study were C3H/He mice and a syngeneic breast cancer cell line (MM-48). When MM-48 tumor, 5 X 10(6) cells per mouse, was inoculated into the footpad, the footpad gradually increased in size, and half of the mice died within 20 days. The frequencies of metastasis for ipsilateral inguinal lymph nodes, axillary lymph nodes and mesenteric lymph nodes were as follows. On day 3 after tumor inoculation, no metastasis was found in any node. On day 6, all mice had inguinal lymph node metastasis, and half of the mice had metastases to axillary lymph nodes and mesenteric lymph nodes. On day 10, all mice had metastasis to all nodes. When 100KE/kg of OK-432 was administered orally every day, the titer of natural killer activity of mesenteric lymph nodes was remarkably increased after 7 days (from 12.3% to 62.9%). When mice were administered OK-432 simultaneously with tumor inoculation and on each day thereafter, the frequency of metastasis mesenteric lymph nodes was markedly decreased after day 7. It is thus suggested that regional lymph nodes may operate effectively against tumor cell attachment to the nodes.