Its levels are significantly elevated compared to healthy subjects; however, specificity and sensitivity are too low to be used in screening.39,91 According to the recommendations of expert groups for the use of markers in lung cancer, gamma-enolase is recommended as an auxiliary marker in SCLC for differential diagnosis when biopsy is not possible and when other neuroendocrine tumours are excluded. Here, ENO2 is linked to small cell lung carcinoma.