Department of Diagnostic Pathology, Nara Medical University School of Medicine Department of Surgery, Nara Prefectural Mimuro Hospital, Nara Department of Laboratory Medicine and Pathology, Kishiwada City Hospital Departments of Pathology, Hoshigaoka Koseinenkin Hospital, Osaka Department of Diagnostic Pathology, Saiseikai Yahata General Hospital, Fukuoka, Japan.
An evaluation of epidermal growth factor receptor (EGFR) phenotypic expression in malignant pleural and peritonealmesothelioma was undertaken, using immunohistochemical (IHC) and fluorescence in situ hybridization (FISH) analysis. Thirty-eight malignant mesothelioma (MM) specimens were subjected to IHC staining and FISH to evaluate the expression of EGFR protein and gene status. Overall positive IHC reaction was detected in 20/38 (53%) cases, in 11/22 (50%) pleural MM, and in 9/16 (56%) peritoneal MM. Our study confirmed that EGFR membranous expression is a common feature in MM, but not in benign mesothelial lesion. Thirty-seven cases did not show a gene copy number gain. Only one case showed a copy number gain. The protein overexpression of EGFR was not related to a gene copy number gain.