[An immunohistological study on expression of glutathione S-transferase pi (form) in human ovarian carcinoma].

Specimens from 102 cases of ovarian cancer were stained immunohistochemically with a rabbit polyclonal antibody prepared against the placental form of the enzyme glutathione S-transferase (GST-pi). All 28 cases of mucinous adenocarcinoma, 19 of clear cell carcinoma and 4 of malignant transformed dermoid cysts were stained positively with the GST-pi antibody. These tumors are considered to be resistant to chemotherapeutic agents as compared with other epithelial tumors. With regard to the histological grade, the degree of staining was reduced according to the loss of differentiation. An investigation of the relationship between GST-pi stain and the prognosis of the 50 patients with stage 2,3 or 4, according to the Kaplan-Meier method, revealed that the prognosis improved as the staining decreased. In conclusion, results suggested that immunohistochemical staining of GST-pi is correlated with the chemoresistance of the tumor, and may predict the outcome in patients with ovarian cancer.