[Subrenal capsule assay (SRCA) using human lung cancer].

Abstract

SRCA was performed using surgically removed fresh tissues in 26 cases of lung cancer. The histological examination of day 6 xenograft showed that only a few xenografts contained tumor cells because of the host cell infiltration and stroma. For the assay considered as evaluable, we defined that control mice needed to show delta tumor size larger than -0.5 OMU and histological presence of tumor cell more than 50% in the day 6 xenograft. The evaluable assay rate (EAR) was no more than 25% (4/16). By the pretreatment with X-ray irradiation of 3 Gy, host cell infiltration was significantly suppressed. With this procedure however, only 40% (4/10) of EAR was gained. The reason for this low EAR was due to the difficulty to obtain the specimens enriched with tumor cells because of stroma and necrotic tissue. Then we used specimen obtained from the human lung cancer line xenografted in nude mice, which resulted in a high EAR of 84% (16/19). We concluded that SRCA for fresh surgical materials was still difficult. However SRCA for lung cancer line was feasible, especially for in vivo preclinical chemosensitivity test for new agents and decision for new drug combination. SRCA as a disease oriented chemosensitivity test is expected to develop in the future.