Immunological modulation in advanced vaginal cancer by repeated intratumorous administration of Sizofiran

Repeated administrations of Sizofiran (SPG) were performed directly to advanced vaginal carcinoma. By this regimen, the tumor mass regressed dramatically. Therefore, we tried to look for the mechanism of action of this method by means of analysing the tissue-infiltrating lymphocytes. Marked increase in degree of the infiltration was observed by Leu 4 (CD 3) positive cells in cancer tissues. As for its subsets, Leu 3a (CD 4) positive cells proved to be dominantly present, compared with Leu 2a (CD 8) positive cells. Especially, marked infiltration by Leu 3a positive cells was noted into the stroma surrounding the tumor mass, some of them actually being infiltrated into the cancer nests. This strongly suggests that these cells played an important role in the immuno-surveillance. In addition, intra-tumor administration of SPG seems to be one of the effective routes for the treatment of malignant tumors by enhancing the local immune potential. This method will be proposed as a quite reliable clinical approach as the local immunological therapy.