Evaluation of epidermal growth factor receptor in odontogenic tumors and rare soft tissue tumors by immunohistochemical and fluorescence in situ hybridization methods Yumuşak dokunun nadir görülen tümörlerinde ve odontojenik tümörlerde immünohistokimyasal yöntem ve floresan in situ hibridizasyonla epidermal growth faktör reseptör varliğinin gösterilmesi

Oz Purpose: The aim of this study is to investigate the role of epidermal growth factor receptor (EGFR) in odontogenic tumors and rare soft tissue tumors. Material and Methods: 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 and 2010. They were evaluated for immunohistochemical staining of EGFR and the presence of genetic abnormality by FISH method. Results: Eleven cases were positively 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. Conclusion: Our findings highlight that EGFR plays an important role in chordoma pathogenesis in soft tissue tumors. In addition to odontogenic tumors; two cases of vascular neoplasia, composite and retiform hemangioendothelioma, exhibited EGFR gene amplification. Interestingly, there is no avaliable 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.