CORRELATION OF THE SURVIVAL OF OVARIAN-CANCER PATIENTS WITH MESSENGER-RNA EXPRESSION OF THE 60-KD HEAT-SHOCK PROTEIN HSP-60

Purpose: Ovarian carcinomas express the 60-kD heat-shock protein HSP-60 at widely varying levels in different tumors. The aim of this study was to determine whether there was a relationship between expression of HSP-60 and survival in patients with ovarian carcinoma. Materials and Methods: Total RNA and DNA were prepared from 51 epithelial ovarian cancer tissue samples. The expression and structure of the HSP-60 gene were examined by Northern and Southern blot analyses using the carboxyl-terminal portion of this gene as a probe (0.89 kilobases [kb]). HSP-60 expression was correlated with overall survival by the Kaplan-Meier method. Results: The 2.3-kb HSP-60 message was detected in all samples, but there was marked variation from tumor to tumor. Patients were classified into two groups on the basis of HSP-60 expression: group 1 (n = 25) included patients with low expression, and group 2 (n = 26) consisted of patients with high expression. There were no significant differences between the groups with respect to age, cell type, pathologic grade, clinical stage, and previous treatment. After a median follow-up period of 17 months, Kaplan-Meier plots demonstrated a much better survival for group 1 (median, 46.8 months; 41% at 4 years) than group 2 (median, 22.1 months; 16% at 3.9 years), a difference that was highly significant by the Mantel-Haenszel test (P = .00183). Southern blot analysis of these samples showed no amplification or rearrangement of the gene. Conclusion: The level of HSP-60 mRNA expression is a valuable prognostic factor in epithelial ovarian cancer. Variation in the level of expression is not due to amplification of this gene.