| Objectives: Focal adhesion kinase(FAK)has long been thought to be a key regulator of growth factor receptor-and integrin-mediated signals,playing pivotal roles in tumor cells through its kinase activity and scaffolding function.Increased FAK expression and activity has been demonstrated in tumors of various origins,and is often associated with poor prognosis.However,there have been no reports on the aberrant expression of FAK in thymic epithelial tumors(TETs).The aim of the current study was to evaluate focal adhesion kinase(FAK)expression in thymic epithelial tumors and to explore the prognostic significance of FAK.Methods: We investigated FAK expression in 100 formalin-fixed,paraffin-embedded human TET specimens using immunohistochemical analysis with FAK-specific monoclonal antibody 4.47 and analyzed the correlation between FAK expression and clinicopathological parameters(sex,age,tumor size,myasthenia gravis,WHO classification,Masaoka-koga stage).Results: FAK was significantly overexpressed in TETs compared with normal thymus tissues(P<0.001).Moreover,FAK overexpression correlated significantly with advanced stages(stage III,IV;P<0.001)and highly aggressive subtypes(type B2 and B3 thymomas and thymic carcinoma;P<0.001)of TETs.In addition,FAK overexpression was significantly associated with worse 10-year overall survival by using univariate analysis(P<0.001).Multivariate analyses revealed that FAK overexpression was an independent prognostic factor for TETs patients(P=0.034).Conclusions: Our results suggest that FAK plays an important role in tumorigenesis and progression in TETs.FAK can serve as a prognostic biomarker and is a potential therapeutic target in TETs. |
