In the present study, we examined die role of c-erbB-2 for chemoresistance in ovarian cancer. Overexpression of c-erbB-2 mRNA in tumor tissue was associated with a shorter survival of patients with primary ovarian cancer (P = 0.0001, N = 77) and was an independent prognostic factor in the proportional-hazard model (P = 0.035). A significant association between expression of c-erbB-2 mRNA und survival was obtained for the subgroup of patients who received a standard chemotherapy with carboplatin or cisplatin and cyclophosphamide (P = 0.0003). In addition, the application of a standard chemotherapy improved the survival of patients with relatively low c-erbB-2 expression (P = 0.013), but not of patients with overexpression of c-erbB-2 (P = 0.359). Expression of c-erbB-2 mRNA correlated with expression of topoisomerase IIalpha mRNA determined by a reverse semiquantitative PCR technique (P = 0.009), whereas expression of c-erbB-2 und topoisomerase IIbeta mRNA dit not correlate (P = 0.221). The data suggest that topoisomerase IIalpha, which correlates with c-erbB-2 expression, contributes to the resistance of c-erbB-2-overexpressing carcinomas.