Serum NSE is directly proportional to brain damage caused by conditions such as cerebral ischemia, and it is an important biological marker of severe brain injury.[16,17] In addition, NSE is a highly specific marker to be used in diagnosis and prognosis of malignant tumors.[18] Serum NSE has been associated with melanoma, seminoma, renal cell carcinoma, Merkel cell tumor, carcinoid tumors, dysgerminomas and immature teratomas, and malignant pheochromocytoma, especially those arising in small cell lung cancer (SCLC).[19] However, there are few studies regarding the value of NSE in GC and CRC. The gene discussed is ENO2; the disease is carcinoid tumor.