Abnormal circulating enzyme concentration or activity Elevated circulating neuron-specific enolase concentration 2023-09-17T13:48:24Z Neuron-specific enolase high in blood Neuron-specific enolase (NSE) is an important tumor marker in the serum of patients with lung cancer. Elevated serum NSE levels are also associated with neuroblastoma, neuroendocrine neoplasms, renal cell carcinoma, multiple myeloma, brain trauma, Guillain-Barre syndrome, and other diseases. Concentration of neuron-specific enolase above the upper limit of normal in the blood circulation.