PTGS2 and lung carcinoma: Epidermal growth factor receptor (EGFR) and cyclooxygenase-2 (COX-2), which can regulate growth, invasion and metastasis of tumor through relevant signaling pathway, have been detected in a variety of solid tumors.The aim of this study is to investigate the biological significance of EGFR and COX-2 expression in lung cancer and the relationship between them.