ENO2 and neoplasm: Serum tumor markers including carcinoembryonic antigen (CEA) [10, 11], neuron-specific enolase (NSE) [12], cytokeratin-19 fragments (Cyfra21-1) [13, 14] and squamous cell carcinoma antigen (SCCA) [15], have been considered to be predictive or prognostic in NSCLC, although no consensus has been reached.