title: Glutathione S-transferase pi immunostaining of cisplatin-resistant ovarian cancer cells in ascites.
abstract: OBJECTIVE
  To clarify immunohistochemically the correlation between glutathione S-transferase pi (GST pi) expression of surgically resected specimens and clinical response in ovarian cancer and to evaluate ascites cytology using GST pi staining.
  
  
  METHODS
  Eighty-seven patients with ovarian cancer underwent initial debulking surgery and received cisplatin-based chemotherapy after surgery. Immunostaining for GST pi was performed on formalin-fixed sections of the patients' tumors. The cytologic slides of 24 cases were acquired for evaluation of GST pi staining.
  
  
  RESULTS
  Of 87 surgically resected specimens, 55 (63.2%) were GST pi positive. Twenty-five of 28 patients (89.3%) who showed no response to chemotherapy had GST pi-positive tumor cells. The predictive value of positive GST pi staining for drug resistance was 75.8% (25/33). Of 18 cases that were GST pi positive in surgically resected specimens, 17 were positive in ascites cytology. Five cases were negative in both resected specimens and ascites cytology. There was a significant correlation in the GST pi labelling index between resected specimen and ascites cytology from the same case; the correlation coefficient was .701 and P value < .001.
  
  
  CONCLUSIONS
  Overexpression of GST pi is related to resistance to cisplatin, and GST pi staining of ascites cytology can be used in pretherapeutic assessment of patients with ovarian cancer.
authors.affiliation: Department of Obstetrics and Gynecology, Niigata University School of Medicine, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Kase
authors.forename: S
authors.initials: S
authors.lastname: Kodama
authors.forename: E
authors.initials: E
authors.lastname: Nagai
authors.forename: K
authors.initials: K
authors.lastname: Tanaka
mesh_terms: D000328:Adult; D000970:Antineoplastic Agents / Q000008:administration & dosage*; D001201:Ascites / Q000201:enzymology / Q000473:pathology; D002945:Cisplatin / Q000008:administration & dosage*; D003536:Cystadenocarcinoma / Q000201:enzymology / Q000473:pathology* / Q000601:surgery; D019008:Drug Resistance, Neoplasm; D005260:Female; D005982:Glutathione Transferase / Q000032:analysis* / Q000276:immunology; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D010051:Ovarian Neoplasms / Q000201:enzymology / Q000473:pathology* / Q000601:surgery
chemical_list: D000970:Antineoplastic Agents; D005982:Glutathione Transferase; D002945:Cisplatin