Thrombospondin-1 and-2 messenger RNA expression in normal and neoplastic endometrial tissues: Correlation with angiogenesis and prognosis

The role of thrombospondin (TSP) in tumor angiogenesis and progression rema ins controversial. The expression of TSP-1 and TSP-2 mRNAs was assessed. Fu rthermore, TSP association with clinicopathological features, including mic rovessel count, regarding prognostic significance was examined. Expression of TSP-1 and TSP-2 were assessed by reverse transcriptase-polymerase chain reaction in 18 normal endometrium and 55 endometrial cancer samples. Microv essel counts were determined by immunostaining for factor VIII-related anti gen in endometrial cancer specimens. TSP-1 expression of secretory phase en dometrium was markedly higher than that of proliferative phase endometrium (p=0.047). Expression of TSP-1 and TSP-2 was detected in 33 (60.0%) and 15 cases (27.3%), respectively, of 55 endometrial cancer samples. TSP-1 expres sion was significantly higher in tumors recovered from elderly women (p=0.0 09). TSP-2 expression was significantly higher in malignancies exhibiting c ervical and lymph-vascular space involvement (p=0.029 and p=0.009, respecti vely). Although not statistically significant, microvessel counts were high er in cases displaying increased TSP-1 expression. The microvessel count in patients with TSP-2 expression was markedly higher than that observed in p atients lacking TSP-2 expression (p=0.026). Subjects demonstrating TSP-2 mR NA expression displayed significantly poorer prognosis than those lacking T SP-2 mRNA expression (p=0.016). There was no association between TSP-1 mRNA expression and patient outcome. Our findings provide evidence that elevate d TSP expression may be associated with an angiogenic phenotype in endometr ial cancer. In addition, TSP-2 expression is a marker for poor prognosis in this disease.