NSE is also known as neuron-specific enolase, which is a human tumor marker and an antigen associated with small cell lung cancer, therefore, elevated NSE often indicates small cell lung cancer and is a tumor marker for clinical detection of small cell lung cancer. In this case, it is necessary to improve the auxiliary examinations, such as reviewing the patient’s tumor series, chest X-ray, lung CT, or endoscopy or taking tissues for pathological examination, to make early diagnosis and early treatment to avoid delaying the disease. In addition, NSE is also a marker of neuroblastoma and can help diagnose neuroblastoma.