C-erb-B2, CD117 and EGFR expressions and clinicopathological approach in thymic tumors

Thymic epithelial neoplasms, accounting less than 1% of all malignancies,originate from thymic epithelial elements and are accompanied by lymphocytes indifferent proportions. The average age is 49.5 years and the incidence can beequal in both sexes or slightly higher in women.was found to be an important prognostic factor for the clinical behavior. Due to itshigh expression in thymic cancer, CD117 was shown to be useful in thedifferential diagnosis and expressions of C-erb-B2 and EGFR were found to besimilar to the literature.We conclude that, despite the small number of patients, our study will be aguiding document for the diagnosis, prognosis and treatment of thymic epitheliallesions and will be a useful source for future studies about the diagnosis,differential diagnosis and treatment of thymic epithelial neoplasms.In our study, 34 cases which had been diagnosed as thymoma or thymiccarcinoma between 2004-2012 at the Pathology Department of Gazi UniversityMedical Faculty were examined. Histopathological features of all patients wereevaluated and re-classified according to 2004-WHO criteria. Cases of thymomaand thymic carcinoma were staged according to 1994 Modified Masaoka systemand 1999 WHO / TNM classification, respectively.Possible prognostic factors for thymic epithelial tumors, such as tumorstage, WHO histological type, age, gender, smoking, necrosis and tumor size,were statistically evaluated and correlated with the literature. In addition,immunohistochemical expression of c-erb-B2, CD117 and EGFR were analyzedin order to search for novel molecular targeted therapies in thymic epithelialneoplasms and particularly for the differential diagnosis of thymic cancers.As a result, the new WHO classification, correlated with Masaoka staging,