Clinical significance of elevated serum chromogranin A levels

Background: Chromogranin A (CgA) has been shown to be a useful marker in the diagnosis of neuroendocrine ( NE) tumours. The clinical significance of CgA has been studied mostly in patients with known NE tumours. The diagnosis was evaluated in 153 consecutive patients in whom CgA was measured in a given time interval. Methods: CgA in serum was measured by radioimmunoassay. Immunohistochemistry with an antibody against CgA was performed in tumours from patients with adenocarcinoma and elevated CgA levels using a conventional method and the more sensitive tyramide signal amplification (TSA) technique. Results: Elevated serum CgA levels were found in 44 patients; 19 had NE tumours and 6 had tumours classified as adenocarcinomas. With the TSA technique, a high proportion of CgA-positive cells were disclosed in five of the adenocarcinoma patients. Patients with atrophic gastritis ( no. 2) and patients treated with inhibitors of gastric acid secretion ( no. 6) also had elevated levels of CgA. A modest increase in CgA levels was observed in 2 patients with renal impairment, and in 9 patients without any obvious cause. Conclusion: The current study confirms that serum CgA is a sensitive marker for the detection of NE neoplasia. Elevated levels found in patients with adenocarcinoma may indicate NE differentiation in the tumour. CgA is a useful tool in the monitoring of enterochromaffin-like (ECL) hyperplasia secondary to treatment with acid secretion inhibitors or atrophic gastritis.