Expression of glutathione s‐transferasepi and sensitivity of human gastric cancer cells to cisplatin

Background. The authors examined the correlation between the expression of glutathione S‐transferase‐pi (GSTπ) and the sensitivity of gastric cancer to anticancer agents. Methods. In 62 human gastric carcinomas, the expression of GSTπ 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‐π‐positive tumors were noted in 35 of 62 excised tumors. There was no significant correlation between GST‐π‐expression and clinicopathologic features or prognosis. The succinate dehydrogenase activity of each drug for tumors, with regard to negative or positive GST‐π, 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 GSTπ and a stronger immunohistochemical staining than CHO cells. Conclusions. The overexpression of GST‐π is significantly related to the sensitivity of gastric cancer to CDDP.