A is produced by a variety of normal and malignant
neuroendocrine and sympathetic neuronal cells and may serve as
a clinically useful marker for hormone-negative endocrine
Elevated levels of Chromogranin A
are seen in neuroendocrine tumours, including
phaeochromocytoma, medullary carcinoma of thyroid, pancreatic
islet cell adenoma, carcinoid tumour, anterior pituitary
adenoma, carotid body tumour, small cell carcinoma of the lung
Minor increases are seen in essential hypertension.
Chromogranin A concentrations rise markedly in patients with
renal failure. Chromogranin B measurements complement
Chromogranin A and are useful in evaluation of falsely
elevated levels of Chromogranin A which may be found in
patients with decreased renal function and treatment with
proton pump inhibitors.