Nuclear localisation of glutathione S-transferase pi is an evaluation factor for drug resistance in gynaecological cancers.

ABSTRACT

AIMS: Nuclear glutathione S-transferase pi (GST7pi) has been reported to protect cancer cells against anticancer drugs. The aim of the present study was to evaluate the clinical significance of nuclear GSTpi in gynaecological cancer. MATERIALS AND METHODS: We carried out an immunohistochemical analysis of GSTpi, and examined the correlation between nuclear GSTpi expression and prognosis in 43 epithelial ovarian cancers. We compared expression levels before and after chemotherapy in uterine cervical cancers and endometrial cancers. RESULTS: The 5-year progression-free survival rate of the nuclear GSTpi-positive group was lower than that of the cytoplasmic GSTpi-positive group, and was significantly lower than that of the negative group (14.3% vs 34.8% vs 66.7%; P = 0.041). The expression of nuclear GSTpi was compared before and after chemotherapy in uterine cervical and endometrial cancers. In eight out of 12 cases (66.7%), the expression turned positive after the chemotherapy. CONCLUSIONS: We suggest that nuclear localisation of GSTpi is associated with drug resistance. The nuclear localisation of GSTpi in tumour cells is a useful prognosticator, and may contribute to the selection of anticancer drugs for gynaecological cancers.