Inhibition by streptococcal immunopotentiator OK432 of lymph-node metastasis in hamster cheek-pouch carcinoma with enhancement of tumour necrosis factor-α and interleukin-6 in serum

A well-known metastatic model of human oral cancer employs 9,10-dimethyl-1,2-benzanthracene (DMBA) to induce hamster cheek-pouch carcinoma. Streptococcal immunopotentiator OK432 was studied here for its inhibitory effect on lymph-node metastasis in that model. The intraperitoneal administration of OK432, after excision of cheek-pouch tumours induced by DMBA, resulted in a marked reduction in the incidence of cervical lymph-node metastasis to 7%, a significant decrease beneath the rates observed for control animals not receiving OK432 (40%). OK432 also caused an increased in serum levels of tumour necrosis factor-α and interleukin-6 in tumour-bearing hamsters. These results suggest that the immune response may play an important part in the antimetastatic effects of OK432.