Clinical study on the effect of intratumoral administration of OK-432 on breast cancer--anti-tumor immune response at the site of local injection]

To elucidate the mechanism of tumor reduction and local immune response after administration of OK-432 into the lesions of breast cancer, patients were given intratumoral injection of OK-432 before surgery. And precise identification of infiltrative lymphocytes was performed. The subjects were 25 patients with primary breast cancer. These patients were randomly divided into the following 3 groups: 10 patients given intratumoral injection of OK-432, 5 patients given intratumoral injection of physiological saline and 10 patients give no treatment. After operation frozen specimens of each tumor were subjected to simple immunohistochemical staining with Leu 2a, Leu 3a and Leu 7, and to immunohistochemical double staining with combination of Leu 2a x Leu 15 and Leu 3a x Leu-DR. Examination of infiltrative lymphocytes in the tumor revealed the positive rate was 100% for Leu 2a + cells (strongly positive, 70%), 90% for Leu 3a + cells (strongly positive, 70%) and 90% for Leu 7 + cells (strongly positive, 0%) in patients given intratumoral injection of OK-432. Double staining showed cytotoxic T cells and helper T cells were predominant among Leu 2a + cells and Leu3a + cells, respectively. Cytotoxic T cells, helper T cells and NK cells were induced at the tumor site after intratumoral injection of OK-432, suggesting the antitumor immune response of these cells is involved in tumor reduction following local administration of OK-432.