TROP2: a novel prognostic marker in squamous cell carcinoma of the oral cavity

Squamous cell carcinoma is by far the most common type of cancer of the oral cavity, representing more than 90% of all oral cancers. Despite refinement of surgical techniques and adjuvant therapies, the prognosis for patients with oral squamous cell carcinoma remains poor. Identification of prognostic factors related to tumor biology might improve this assessment. Recently, the human trophoblast cell-surface antigen TROP2 was found to be highly expressed in colorectal cancer, correlating with aggressiveness and poor prognosis. Thus, the aim of this study was to investigate TROP2 expression and its prognostic impact in oral squamous cell carcinoma patients. TROP2 expression was examined by immunohistochemistry in a series of 90 patients on a tissue microarray of paraffin-embedded specimens. Survival was calculated using Kaplan-Meier estimates. Parameters found to be of prognostic significance in univariate analysis were verified in a multivariate Cox regression model. TROP2 overexpression was observed in 52 (58%) of the tumor samples. Kaplan-Meier curves showed that TROP2 overexpression was significantly associated with decreased overall survival (P<0.01). Overall survival gradually worsened with increasing TROP2 scores. By univariate analyses, no correlation with conventional clinicopathological features was found. Multivariate Cox regression analysis revealed TROP2 overexpression to be an independent factor predictive of poor disease outcome (P<0.01). These results demonstrate that TROP2 overexpression is an independent prognostic marker in patients with oral squamous cell carcinoma. TROP2 overexpression was detectable in 58% of the tumor samples, indicating it to be a potential novel therapeutic target in squamous cell carcinoma of the oral cavity.