Neuron-specific enolase(NSE) is a tumor marker for neuroblastoma and also one of the mostsensitive and specific marker for small-cell lung cancer(SCLC) which has neuroendocrine properties withover-expressing of NSE. Quantitative assay for circulating NSE has clinic significance in monitoring oftherapy and prognosis for the cancer. Neuron-specific enolase (NSE) is a tumor marker for neuroblastoma and also one of the most sensitive and specific markers for small-cell lung cancer (SCLC) which has neuroendocrine properties with over-expressing of NSE. Quantitative assay for circulating NSE has clinic significance in monitoring oftherapy and prognosis for the cancer.