BACKGROUND: The authors examined the correlation between the expression of glutathione S-transferase-pi (GST pi) and the sensitivity of gastric cancer to anticancer agents. METHODS: In 62 human gastric carcinomas, the expression of GST pi was immunohistochemically evaluated, and sensitivity to the anticancer drugs, cisplatin (CDDP), doxorubicin (DXR) aclacinomycin A (aclarubicin), (ACR), 5-fluorouracil (5-FU), mitomycin C (MMC) and carboquone (carbazilquinon) (CQ) was examined using the in vitro succinate dehydrogenase inhibition test. The authors used the Chinese hamster ovary (CHO) cell line and its variant CDDP-resistant cell line C/CDP-2, and they analyzed the relationship among CDDP-sensitivity, mRNA expression, and immunohistochemical staining. RESULTS: Immunohistochemically detected GST-pi-positive tumors were noted in 35 of 62 excised tumors. There was no significant correlation between GST-pi expression and clinicopathologic features or prognosis. The succinate dehydrogenase activity of each drug for tumors, with regard to negative or positive GST-pi, was 34.9 plus or minus 13.7% and 46.0 plus or minus 22.0% for CDDP, with a significant statistical difference (P < 0.05). However, there was no statistical difference for the other drugs tested. C/CDP-2 cells showed a lower sensitivity to CDDP, a higher expression of mRNA for GST pi and a stronger immunohistochemical staining than CHO cells. CONCLUSIONS: The overexpression of GST-pi is significantly related to the sensitivity of gastric cancer to CDDP.
BACKGROUND: The authors examined the correlation between the expression of glutathione S-transferase-pi (GST pi) and the sensitivity of gastric cancer to anticancer agents. METHODS: In 62 humangastric carcinomas, the expression of GST pi was immunohistochemically evaluated, and sensitivity to the anticancer drugs, cisplatin (CDDP), doxorubicin (DXR) aclacinomycin A (aclarubicin), (ACR), 5-fluorouracil (5-FU), mitomycin C (MMC) and carboquone (carbazilquinon) (CQ) was examined using the in vitro succinate dehydrogenase inhibition test. The authors used the Chinese hamster ovary (CHO) cell line and its variant CDDP-resistant cell line C/CDP-2, and they analyzed the relationship among CDDP-sensitivity, mRNA expression, and immunohistochemical staining. RESULTS: Immunohistochemically detected GST-pi-positive tumors were noted in 35 of 62 excised tumors. There was no significant correlation between GST-pi expression and clinicopathologic features or prognosis. The succinate dehydrogenase activity of each drug for tumors, with regard to negative or positive GST-pi, was 34.9 plus or minus 13.7% and 46.0 plus or minus 22.0% for CDDP, with a significant statistical difference (P < 0.05). However, there was no statistical difference for the other drugs tested. C/CDP-2 cells showed a lower sensitivity to CDDP, a higher expression of mRNA for GST pi and a stronger immunohistochemical staining than CHO cells. CONCLUSIONS: The overexpression of GST-pi is significantly related to the sensitivity of gastric cancer to CDDP.