Endoscopic intratumoral injection of OK-432 and Langerhans' cells in patients with gastric carcinoma.

OK-432, a compound composed of penicillin-G-treated, attenuated Streptococcus pyogenes of human origin, was administered by intratumoral injection (IT) to 15 of 49 patients with Stage III gastric carcinoma, at the time of preoperative endoscopic examination. The 5-year survival rate of patients given IT was 73.3%, whereas the rate was only 36.5% in those not given IT (P less than 0.05). A study of recurrent cases revealed a significantly low incidence of peritoneal recurrence in the group on OK-432 IT (P less than 0.01). In previous work, the authors noted a favorable prognosis of patients with Stage III gastric carcinoma and with a marked infiltration of Langerhans' cells (LC) in the tumor tissues. All of the 49 in the current study were thus examined immunohistochemically, using anti-S-100 protein antibody, the objective being to clarify the relationship between OK-432 IT and the density of LC. The density of LC among those given IT was significantly increased as compared with those not given IT (P less than 0.05). The results of this study suggest that OK-432 IT may lead to augmentation of the density of LC in tumor tissues and hence prevent peritoneal recurrences in patients with Stage III gastric carcinoma.