The clinical significance of neuron-specific enolase (NSE)

        NSE is an acid protease, which is involved in glycolysis and metabolism. The glycolysis of tumor tissues is enhanced, the cell proliferation cycle is accelerated, and the release of NSE in the cells into the blood increases. Tumors originating from neuroendocrine tissues, such as neuroblastoma and small cell lung cancer (SCLC), have elevated serum NSE.

1. Screening
        Serum NSE is generally not used for lung cancer screening.
 
2. Auxiliary diagnosis
        ① Serum NSE is one of the first choice markers for small cell lung cancer (SCLC). The level of NSE in patients with small cell lung cancer is significantly higher than that of non-small cell lung cancer (NSCLC) such as lung adenocarcinoma, lung squamous cell carcinoma, and large cell lung cancer, which has auxiliary diagnostic value. It can also be used for the differential diagnosis of small cell lung cancer and non-small cell lung cancer.
        ② Serum NSE is also a tumor marker of neuroblastoma, which is significantly higher in patients, while it is less frequent in patients with Wilms tumor. Therefore, it can be used for the differential diagnosis of neuroblastoma and Wilms tumor.
        ③ Elevated serum NSE is also common in neuroendocrine cell tumors, such as pheochromocytoma, medullary thyroid carcinoma, melanoma, islet cell tumor, and retinoblastoma.
        ④ Serum NSE can also be increased in certain neurological diseases and lung diseases, such as meningitis and pneumonia, but the percentage of positive is low.

3. Prognosis assessment
        Serum NSE is an important prognostic indicator for small cell lung cancer and neuroblastoma. Serum NSE continues to rise, suggesting a poor prognosis.
 
4. Efficacy and recurrence monitoring
        ① Serum NSE level can reflect the response to chemotherapy of small cell lung cancer. A temporary increase of NSE (tumor disappearance) can occur 24h to 72h after chemotherapy. The serum NSE level of patients with a good response to chemotherapy will drop rapidly after the end of the first course of treatment. The continuous increase or temporary decrease of the patient's NSE level indicates that the treatment effect is not good.
        ② Serum NSE can be used for follow-up and recurrence monitoring of small cell lung cancer. Generally, it should be tested every 3 months within 2 years after treatment, and every 6 months within 3 to 5 years.