In addition to the aforementioned tumor indicators, serum markers include carcinoembryonic antigen (CEA), nerve-specific enolase (NSE), cytokeratin 19 fragment (CYFRA 21-1), squamous cell carcinoma antigen (SCC-Ag), and pro-gastrin-releasing peptide (ProGRP) [59]. This evidence concerns the gene ENO2 and neoplasm.