ENO2 and neoplasm: Neuron-specific enolase (NSE) and ProGRP are currently used as tumor biomarkers for SCLC diagnosis, but they have poor sensitivity and specificity to predict SCLC disease.3-11 Although the predictive ability of ProGRP is higher than that of NSE, the diagnostic sensitivity of ProGRP varied within the range of 54%-78%, with diagnostic specificity of 72%-99%.12 In addition, other non-neuroendocrine makers, such as caspase cleaved cytokeratin 19 (CYFRA21-1) and lactate dehydrogenase (LDH), are commonly used to diagnose SCLC.