9614 Background: Epidermal growth factor receptor (EGFR) is widely overexpressed in various cancers, and reported to relate with growth and invasion of cancer cells. However, clinical significance of EGFR overexpression is still controversial because its correlation with prognosis is not universal. Thus, activated form of EGFR (phosphorylated EGFR, p-EGFR) may better predict prognosis. We determined the association of p-EGFR and prognosis, and its relationship with EGFR and COX-2, and other biomarkers. Methods: We immunohistochemically examined the expression of p-EGFR, EGFR, and COX-2 in 77 resected stage I/II non-small cell lung cancers (NSCLCs). Their correlation with prognosis and other biomarkers was also assessed including Ki-67, vascular endothelial growth factor (VEGF), and microvessel density (MVD). Results: EGFR overexpression, defined as membranous staining in more than 10% of cancer cells, was found in 37 patients (48.1%). 45 patients (58.4%) showed COX-2 overexpression, cytoplasmic granular s...