[Fundamental studies of subrenal capsule assay]

Cancer chemosensitivity test by Bogden's SRCA (subrenal capsule assay) method was experimentally evaluated using DMBA induced rat ovarian cancer. Cancer tissues were implanted beneath the renal capsule of BDF1 mice, and factors affecting development of the xenografts were examined. To observe the effect of the host-mediated immunologic reaction, the mice were put into immunosuppressive situations by applying cyclophosphamide (CPA) or cyclosporin A (CsA), and the growth of the tumor in each condition received macroscopic and histological evaluation. Under the most favorable conditions, drug sensitivity tests were performed. The results obtained were as follows: 1) In non-treated mice, the cancer cells of the grafted tumor were rejected, until the 7th day following the implantation, by host reaction. 2) In a CPA-induced immunosuppressive condition, the tumor tissue was damaged by the cytotoxic effect, although the size of the tumor was on the increase until the 9th day. 3) CsA brought about a favorable condition for tumor development, showing a linear growth curve from the 3rd to the 9th day with viable cancer cells. 4) Chemosensitivity tests indicated that methotrexate and CDDP were effective, while mitomycin was not effective in treating the implanted tumors. 5) The results obtained with SRCA were much the same in experimental therapeutic trials using rats with primary ovarian cancer induced by DMBA application.