Purpose: In a previous pilot study, HSP60 expression at the transcriptional (mRNA) level was shown to be a negative prognostic factor in ovarian cancer. The aim of this study was to determine HSP60-expression by means of immunohistochemistry and to correlate the results with survival in a large series of ovarian carcinoma patients with a closed follow-up.
Materials and methods: Slides from routinely processed, paraffin-embedded tumor blocks belonging to 247 patients with epithelial ovarian carcinoma were studied for the overexpression of HSP60 using the Lk2 monoclonal antibody and the strepatvidin-biotin-peroxidase technique. HSP60-expression was correlated with overall survival by means of life-table analysis and the Kaplan-Meier method.
Results: 47 tumors (19%) expressed HSP60. Of them, 12/29 (41.4% positivity) were stage I tumors, whereas only 35 out of the remaining 218 tumors in more advanced surgical stage (16.1%) showed HSP60 staining. This difference was statistically significant (Fisher s exact test; p = 0.004). Even when stratifying stage for stage, the difference between groups still remained statistically significant (Chi square test; p = 0.0095). The survival curve analysis showed a significant difference in favor of those tumors expressing HSP60 (median survival 28 vs. 37 months; log-rank test, p = 0.02).
Conclusion: Immunohistochemical detection of HSP60-expression in human epithelial ovarian carcinoma is significantly more frequent in tumors from patients with initial stages of the disease. Therefore, HSP60-expression determined by this method is associated with a significantly better prognosis.