Objectives: Cancer-testis (CT) antigens are expressed in tumors but not normal tissues except the testis and could be targets for vaccine therapy in epithelial ovarian cancer (EOC). A-kinase anchoring protein 3 (AKAP-3) is a novel member of the CT antigen family. The aim of this study was to examine the expression of AKAP-3 in EOC and correlate with clinico-pathologic characteristics.
Methods: One step RT-PCR was performed with RNA from normal and ovarian cancer cell lines and 74 epithelial ovarian tumor tissues. AKAP-3-specific PCR product was amplified. The distribution of AKAP-3 expression and clinico-pathologic variables was analyzed. Survival distributions were estimated, and multivariate analyses were performed.
Results: AKAP-3 mRNA expression was demonstrated in 43/74 (58%) of the ovarian cancer specimens. AKAP-3 was expressed in normal testis, but not in other normal tissues. AKAP-3 expression significantly correlated with increased likelihood of residual tumor (P = 0.005), but no increase in the likelihood of recurrence or persistent disease (P = 0.06). Patients with AKAP-3 mRNA expression were found to have a significantly poorer overall survival (median 50 months) compared with patients without AKAP-3 expression (median not reached) (P = 0.007). Multivariate analysis of AKAP-3 expression, residual disease, and response to frontline chemotherapy found response to be the strongest predictor of overall survival (P = 0.012).
Conclusions: Our data demonstrate that AKAP-3 is expressed at high frequency in patients with EOC. Since AKAP-3 demonstrates tumor-restricted expression and appears to be associated with worse overall survival, it could represent an attractive target for antigen-specific immunotherapy in EOC.