Plasma chromogranin A in prostatic carcinoma and neuroendocrine tumors.

PURPOSE

Chromogranin A is a good tumor marker for neuroendocrine cells. Whether plasma chromogranin A could be a useful marker for neuroendocrine differentiation of prostatic carcinoma and neuroendocrine tumors was investigated using an enzyme-linked immunosorbent assay.

MATERIALS AND METHODS

Plasma levels of chromogranin A were measured by enzyme-linked immunosorbent assay in 33 patients with prostatic carcinoma, 10 with benign prostatic hyperplasia (BPH) and 13 with neuroendocrine tumors (2 medullary thyroid carcinomas, 1 thymic carcinoid, 1 gastrin producing duodenal carcinoid, 3 nonfunctioning pancreatic endocrine tumors, 2 neuroblastomas, 3 pheochromocytomas and 1 carotid body tumor).

RESULTS

The normal level of chromogranin A from 40 healthy volunteers was 30 +/- 11 units per 1. (mean plus or minus standard deviation). Mean plasma chromogranin A in patients with BPH and prostatic carcinoma was 52.4 +/- 12.9 and 67.5 +/- 22.9 units per 1., respectively. All patients with neuroendocrine tumors, except 1 with a nonfunctioning pancreatic endocrine tumor, had elevated chromogranin A (mean 401 +/- 409 units per 1.). There were significant differences in plasma chromogranin A level between patients with BPH and neuroendocrine tumors (p < 0.01), prostatic carcinoma and neuroendocrine tumors (p < 0.01), and BPH and prostatic carcinoma (p < 0.05). Of the 33 patients with prostatic carcinoma 5 had elevated chromogranin A, only 1 of whom had elevated prostate specific antigen.

CONCLUSIONS

Chromogranin A is an excellent marker for neuroendocrine tumors, particularly nonfunctioning tumors, and measurement of chromogranin A is also useful to detect prostatic carcinoma in patients whose prostate specific antigen is not elevated.