30. MAL2 and tumour protein D52 (TPD52) overexpression in ovarian carcinoma, association with histological subtype and clinical outcome

Abstract

Background MAL2 protein is frequently overexpressed in breast carcinoma, and MAL2 overexpression is associated with gain of the corresponding locus at chromosome 8q24.12. Independent expression microarray studies predict MAL2 overexpression in ovarian carcinoma, but this has not been confirmed. MAL2 binds tumour protein D52 (TPD52), which is frequently overexpressed in ovarian carcinoma, but the clinical significance of TPD52 over-expression is unknown. We sought to assess immunohistochemical expression of MAL2 and TPD52 in a range of ovarian tumours, and to correlate their expression with survival. Methods Immunohistochemical analyses of MAL2 and TPD52 expression were performed on tissue microarray sections of benign, borderline and malignant epithelial ovarian tumours. Staining intensity and distribution was assessed both visually and digitally. Results MAL2 and TPD52 expression was significantly higher in high-grade serous carcinomas (SCs) than in serous borderline tumours. MAL2 expression was highest in SCs relative to other histological subtypes, whereas TPD52 expression was highest in clear cell carcinomas. High-level TPD52 expression was significantly associated with improved overall survival in stage III SC patients (log-rank test, p n = 124), and was an independent predictor of improved survival in the overall carcinoma cohort (hazard ratio 0.498, 95%CI 0.34–0.73; p n = 221) and in SCs (hazard ratio 0.44; 95%CI 0.29–0.66; p n = 182). Conclusions MAL2 overexpression is frequent in ovarian carcinoma, and TPD52 overexpression is a favourable prognostic marker.