Objective The aim of this study is to evaluate the clinical value of the serum level of Chromogranin A(CgA) for the diagnosis of gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs). Materials and Methods 58 patients with GEP-NENs were enrolled in this prospective study. 30 patients with gastrointestinal diseases and 30 healthy adults were served as control group. Serum CgA was measured by enzyme-linked immunosorbent assay (ELISA) in all patients. Of 58 patients with GEP-NENs, the clinical characteristics including G staging, Ki67 and tumor marker was followed-up, final diagnosis was confirmed by histopathology. Results CgA in GEP-NENs were significantly higher than that in control group, moreover, CgA in G2 staging were significantly higher than that of G1（129.5 ng/ml vs. 61. 1 ng/ml ,P<0.05）,no significant difference was found between G3 and G1-2 staging. If 53.5 ng/mL was used as cut-off or threshold, the sensitivity and specificity of CgA for screening of NENs was 70.7%, 73.3%, respectively. CgA was significantly higher in gastroitntestinal NENs than that of pNENs (115.3ng/ml, 67.1 ng/ml). Conclusions CgA serve as a reliable biomarker for the diagnosis and follow-up of GEP-NENs and may provide additional information for evaluation of G staging. Serum of CgA of 53.5 ng/mL was used as threshold, which might improve\ sensitivity and specificity in the diagnosis of GEP-NENs. Due to small population and single centered research, further study is needed.

Key words: Chromogranin A, Neuroendocrine neoplasm, gastroenteropancreatic endocrine tumor