EGFR expression: Associations with outcome and clinicopathological variables in malignant pleural mesothelioma

Lung Cancer, Volume 54, Issue 3, Pages 399-407

J.G. Edwards^a,b, D.E.B. Swinson^a, J.L. Jones^c, D.A. Waller^b, K.J. O’Byrne^d

• ^a Department of Oncology, University of Leicester, Leicester, United Kingdom
• ^b Department of Thoracic Surgery, University Hospitals Leicester NHS Trust, Glenfield Hospital, Leicester, United Kingdom
• ^c Institute of Cancer, Barts and The London NHS Trust, Queen Mary’s School of Medicine and Dentistry, Charterhouse Square, London EC1M 6BQ, United Kingdom
• ^d HOPE Directorate, St. James’s Hospital, P.O. Box 580, James’s Street, Dublin 8, Ireland

Abstract

Malignant mesothelioma (MM) is a fatal tumour of increasing incidence which is related to asbestos exposure. This work evaluated expression in MM of Epidermal Growth Factor Receptor (EGFR) by immunohistochemistry in 168 tumour sections and its correlations with clinicopathological and biological factors. The microvessel density (MVD) was derived from CD34 immunostained sections. Hematoxylin and eosin stained sections were examined for intratumoural necrosis. COX-2 protein expression was evaluated with semi-quantitative Western blotting of homogenised tumour supernatants (n=45). EGFR expression was correlated with survival by Kaplan-Meier and log rank analysis. Univariate and multivariate Cox proportional hazards models were used to compare the effects of EGFR with clinicopathological and biological prognostic factors and prognostic scoring systems. EGFR expression was identified in 74 cases (44%) and correlated with epithelioid cell type (p<0.0001), good performance status (p<0.0001), the absence of chest pain (p<0.0001) and the presence of TN (p=0.004), but not MVD or COX-2. EGFR expression was a good prognostic factor in univariate analysis (p=0.01). Independent indicators of poor prognosis in multivariate analysis were non-epithelioid cell type (p=0.0001), weight loss, performance status and WBC>8.3×10⁹L⁻¹. EGFR status was not an independent prognostic factor. EGFR expression in MM correlates with epithelioid histology and TN. EGFR may be a target for selective therapies in MM.

Keywords: Malignant mesothelioma, Prognosis, Epidermal Growth Factor Receptor