Trop-2 protein overexpression is an independent marker for predicting disease recurrence in endometrioid endometrial carcinoma

BACKGROUND: Endometrial cancer is the most common gynecologic malignancy in developed countries. Trop-2 is a glycoprotein involved in cellular signal transduction and is differentially overexpressed relative to normal tissue in a variety of human adenocarcinomas, including endometrioid endometrial carcinomas (EEC). Trop-2 overexpression has been proposed as a marker for biologically aggressive tumor phenotypes. METHODS: Trop-2 protein expression was quantified using tissue microarrays consisting of formalin-fixed paraffin-embedded specimens from 118 patients who underwent surgical staging from 2001–9 by laparotomy for EEC. Clinicopathologic characteristics including age, stage, grade, lymphovascular space invasion, and medical comorbidities were correlated with immunostaining score. Univariate and multivariate analyses were performed for overall survival, disease-free survival, and progression-free survival in relation to clinical parameters and Trop-2 protein expression. RESULTS: Clinical outcome data were available for 103 patients. Strong Trop-2 immunostaining was significantly associated with higher tumor grade (p=0.02) and cervical involvement (p<0.01). Univariate analyses showed a significant association with reduced disease-free survival (DFS) (p=0.01), and a trend towards significance for overall and progression-free survival (p=0.06 and p=0.05, respectively). Multivariate analyses revealed Trop-2 overexpression and advanced FIGO stage to be independent prognostic factors for poor DFS (p=0.04 and p <0.001, respectively). CONCLUSIONS: Trop-2 protein overexpression is significantly associated with higher tumor grade and serves as an independent prognostic factor for DFS in endometrioid endometrial cancer.