Evaluation of epidermal growth factor receptor in odontogenic tumors and rare soft tissue tumors by immunohistochemical and fluorescence in situ hybridization methods

Odontogenic tumors are rare tumors. They are composed of epithelial, ectomesenchymal and mesenchymal tissue. Soft tissue tumors are heterogenous group of tumors and are named according to the similarity of the tissue origin. Epidermal growth factor receptor (HER1/EGFR) is a transmembrane protein and this plays a prominent role in the control of normal cellular process and in the regulation of many metabolic and physiological processes in a variety of tissues and organs. Overexpression or mutation of EGFR played an important role in many tumor?s pathogenesis.This study includes 28 cases (11 cases of odontogenic tumors and 17 cases of soft tissue tumors) which were diagnosed at Cukurova University Medical Faculty, Department of Pathology between 2002-2010. They are evaluated for immunohistochemical staining of EGFR and the presence of genetic abnormality by FISH method.Eleven cases were stained by immunohistochemistry. Eight cases had genetic abnormality of EGFR gene by FISH method.Nine of eleven odontogenic tumors (%81,8) showed overexpression of EGFR by immunohistochemical method or FISH method. This finding supports role of EGFR in pathogenesis of odontogenic tumors. Also our findings highlighted that EGFR plays an important role at chordoma pathogenesis in soft tissue tumors. Two cases of vascular neoplasia, composite and retiform hemangioendothelioma, exhibited EGFR gene amplification. Interestingly, there is no available data about EGFR gene status in these tumors. EGFR can be used for diagnostic purposes. Also it is a target for anti-EGFR therapy therefore EGFR gene status is a valuable marker for therapeutic management.