[The sensitivity of 1,000 human tumors to antitumor drugs using the succinate dehydrogenase inhibition (SDI) test].

The chemosensitivity was evaluated by the in vitro succinate dehydrogenase inhibition (SDI) test in 1,000 human tumors including 237 gastric cancers, 116 colorectal cancers, 113 hepatoma and 534 others. These tumor cells were exposed to 5 kinds of antitumor drugs, carboquone (CQ), adriamycin (ADM), mitomycin C (MMC), aclacinomycin A (ACR), cis-platinum (DDP). After exposure to the antitumor drugs, cell viability was assessed with colorimetric assay, based on the ability of succinate dehydrogenase (SD) in living tumor cells to reduced a tetrazolium (MTT) to a formazan. The chemosensitivity was determined to be positive when the SD activity of drug exposed cells decreased to below 50% of that of control cells, on day 3 of exposure. The chemosensitivity varied in the tumor tissues. The chemosensitivity of metastatic lesions of lymph nodes were higher than that of the primary lesions, while metastatic liver tumors had lower sensitivity than the primary lesions. The intra-tumorous distribution of SD activity in 12 human gastric cancers were compared with normal adjacent tissues using histochemistry. Seventy-five % (9/12) of gastric cancer tissues had higher SD activity than normal adjacent tissues. The SDI test is rapid and simple method to predict the sensitivity test of various human tumors to antitumor drugs.