Preparation of Samples

Abstract

and hMSH2 in primary resected tumours and residual tumours in women requiring a second excision of ovarian cancer following 5 or 6 courses of CDDP-based postoperative induction chemotherapy to manage an incomplete primary resection. MATERIALS AND METHODS Subjects The subjects of this study were 24 patients with primary epithelial ovarian cancer in whom the primary operation resulted in a noncu-rative resection with residual tumours large enough to be measured for the determination of the efficacy of post-operative induction chemotherapy who were treated in our department from 1989 to 1995. Despite a total 5 or 6 courses of postoperative CDDP-based chemotherapy, we performed secondary cytoreduc-tive surgery at 6 to 8 weeks after the final administration of CDDP-based chemotherapy for the cases with a partial response (PR) and no change (NC). Those with a complete response (CR) or progressive disease (PD) did not undergo secondary cytoreductive surgery. Paired tumour samples from these 2 resections were used to assess the effects of CDDP-based chemotherapy on the tumour's microsatellite instability (MSI) and the protein expres-sion of hMSH2 and hMLH1. In this study, we obtained informed consent from all patients prior to examine the specimens. The clinical stage of each patient was determined according to the classification of the International Federation of Gynecology and Obstetrics (FIGO, 1989). It was stage IIIc in 19 patients and stage IV in 5 patients. The histologic subtypes included serous adenocarcinoma (14 patients), serous papillary adenocarcinoma (3 patients), mucinous adenocarcinoma (1 patient), endometrioid adenocarcinoma (3 patients), clear cell adenocarcinoma (2 patients), and undifferentiated carcinoma (1 patient). The histo-logic grade was G 1 in 4 patients, G 2 in 16 patients, and G 3 in 4 patients. The postoperative chemotherapy regimen was CAP (CDDP 50 mg m –2 , doxorubicin 40 mg m –2 , cyclophosphamide 300 mg m –2), or CP (CDDP 70 mg m –2 , cyclophosphamide 500 mg). All patients received 5 or 6 courses of this regimen (mean: 5.5 courses), and the mean total dose of CDDP administrated was 427.7 ± 19.1 mg (range: 408–480 mg). The assessment of the tumour's response to chemotherapy was based upon the World Health Organization criteria (1979) and was classified as a partial response (PR) in 11 cases and no change (NC) in 13 cases.