Granins and their derived peptides in normal and tumoral chromaffin tissue: Implications for the diagnosis and prognosis of pheochromocytoma.
Pheochromocytomas are rare catecholamine-secreting tumors that arise from chromaffin tissue within the adrenal medulla and extra-adrenal sites. Typical clinical manifestations are sustained or paroxysmal hypertension, severe headaches, palpitations and sweating resulting from hormone excess. However, their presentation is highly variable and can mimic many other diseases. The diagnosis of pheochromocytomas depends mainly upon the demonstration of catecholamine excess by 24-h urinary catecholamines and metanephrines or plasma metanephrines. Occurrence of malignant pheochromocytomas can only be asserted by imaging of metastatic lesions, which are associated with a poor survival rate. The characterization of tissue, circulating or genetic markers is therefore crucial for the management of these tumors. Proteins of the granin family and their derived peptides are present in dense-core secretory vesicles and secreted into the bloodstream, making them useful markers for the identification of neuroendocrine cells and neoplasms. In this context, we will focus here on reviewing the distribution and characterization of granins and their processing products in normal and tumoral chromaffin cells, and their clinical usefulness for the diagnosis and prognosis of pheochromocytomas. It appears that, except SgIII, all members of the granin family i.e. CgA, CgB, SgII, SgIV-SgVII and proSAAS, and most of their derived peptides are present in adrenomedullary chromaffin cells and in pheochromocytes. Moreover, besides the routinely used CgA test assays, other assays have been developed to measure concentrations of tissue and/or circulating granins or their derived peptides in order to detect the occurrence of pheochromocytomas. In most cases, elevated levels of these entities were found, in correlation with tumor occurrence, while rarely discriminating between benign and malignant neoplasms. Nevertheless, measurement of the levels of granins and derived peptides improves the diagnostic sensitivity and may therefore provide a complementary tool for the management of pheochromocytomas. However, the existing data need to be substantiated in larger groups of patients, particularly in the case of malignant disease.
Guérin
Marlène
M
Institut National de la Santé et de la Recherche Médicale (INSERM), U982, Laboratory of Neuronal and Neuroendocrine Differentiation and Communication, European Institute for Peptide Research (IFRMP 23), University of Rouen, Mont-Saint-Aignan, France.
Guillemot
Johann
J
Thouënnon
Erwan
E
Pierre
Alice
A
El-Yamani
Fatima-Zohra
FZ
Montero-Hadjadje
Maité
M
Dubessy
Christophe
C
Magoul
Rabia
R
Lihrmann
Isabelle
I
Anouar
Youssef
Y
Yon
Laurent
L
D000310:Adrenal Gland Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology*; D019439:Chromaffin Cells / Q000378:metabolism* / Q000473:pathology*; D002864:Chromogranins / Q000378:metabolism*; D006801:Humans; D010673:Pheochromocytoma / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology*
D002864:Chromogranins