ENO2 and neoplasm: A range of serum tumor markers (STMs) are used clinically for NSCLC screening and response and recurrence monitoring, e.g., carcinoembryonic antigen (CEA), squamous cell carcinoma antigen (SCC-Ag), cytokeratin 19 fragments (CYFRA 21-1), neuron-specific enolase (NSE) and ferritin [15–17].