Furthermore, improved discrimination of the two main lung cancer subtypes, SCLC and non-small cell lung cancer (NSCLC), was achieved when applying a diagnostic cut-off value of 25 ng/mL NSE or analyzing multiple protein tumor markers such as NSE and progastrin-releasing peptide (ProGRP) at the same time [4, 6–10]. Here, ENO2 is linked to non-small cell lung carcinoma.