Chromogranin A plasma concentration and expression in pancreatic islet cell tumors of dogs and cats.
OBJECTIVE
To describe expression of the neuroendocrine marker chromogranin A (CgA) in canine and feline pancreatic islet cell tumors and their metastases, and to evaluate plasma CgA concentration in dogs and cats with insulinoma.


METHODS
Paraffin-embedded tissues from 25 canine and 2 feline pancreatic islet cell tumors, 5 canine and 6 feline exocrine pancreatic tumors, and normal pancreatic tissue from 2 dogs and 2 cats. Heparinized plasma samples from 3 dogs and 2 cats diagnosed with insulinoma, and 10 control plasma samples from each species.


METHODS
Immunohistochemical analysis was performed on the 42 tissue specimens, using antisera against CgA, neuron-specific enolase, insulin, somatostatin, glucagon, and pancreatic polypeptide. The 25 plasma samples were evaluated, using a soluble-phase, double-antibody, equilibrium radioimmunoassay directed against the amino- and carboxy-terminal peptides of bovine CgA.


RESULTS
Chromogranin A expression was found in 76% of canine and 2 of 2 feline pancreatic islet cell tumors. Of 7 animals with CgA immunoreactivity in primary tumors, 6 also had CgA immunostaining of metastatic lesions. Plasma CgA concentration in 2 dogs with insulinoma (0.9, 1.0 ng/ml) exceeded the reference range established for 10 clinically normal control dogs (0.50 +/- 0.16 ng/ml). Feline plasma CgA samples had extensive nonspecific background immunoreactivity.


CONCLUSIONS
Chromogranin A is a useful immunohistochemical marker for pancreatic tumors of neuroendocrine origin and their metastases. Plasma CgA concentration determined by radioimmunoassay was high in 2 dogs with insulinoma.


CONCLUSIONS
Immunohistochemical staining of tissues or cytologic specimens for CgA and/or neuron-specific enolase may help distinguish masses of unknown origin as neuroendocrine in nature. Increase in plasma CgA concentration may be useful diagnostically for animals with suspected neuroendocrine tumors.
Myers
N C
NC
Department of Clinical Science, College of Veterinary Medicine, Kansas State University, Manhattan 66506, USA.
Andrews
G A
GA
Chard-Bergstrom
C
C
D000818:Animals; D002371:Cat Diseases / Q000097:blood* / Q000235:genetics / Q000378:metabolism; D002415:Cats; D002417:Cattle; D053379:Chromogranin A; D002864:Chromogranins / Q000096:biosynthesis* / Q000097:blood* / Q000276:immunology; D004283:Dog Diseases / Q000097:blood* / Q000235:genetics / Q000378:metabolism; D004285:Dogs; D015972:Gene Expression Regulation, Neoplastic; D005934:Glucagon / Q000032:analysis / Q000276:immunology; D007106:Immune Sera / Q000276:immunology; D007150:Immunohistochemistry; D007328:Insulin / Q000032:analysis / Q000276:immunology; D007340:Insulinoma / Q000097:blood / Q000737:chemistry / Q000662:veterinary*; D010179:Pancreas / Q000737:chemistry / Q000378:metabolism / Q000473:pathology; D010190:Pancreatic Neoplasms / Q000097:blood / Q000737:chemistry / Q000662:veterinary*; D010191:Pancreatic Polypeptide / Q000032:analysis / Q000276:immunology; D010751:Phosphopyruvate Hydratase / Q000032:analysis / Q000276:immunology; D011863:Radioimmunoassay / Q000379:methods / Q000662:veterinary; D013004:Somatostatin / Q000032:analysis / Q000276:immunology
D053379:Chromogranin A; D002864:Chromogranins; D007106:Immune Sera; D007328:Insulin; D013004:Somatostatin; D010191:Pancreatic Polypeptide; D005934:Glucagon; D010751:Phosphopyruvate Hydratase