Clinical significance of elevated serum chromogranin A levels

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.

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.

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.

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.