title: Measurements of secretogranins II, III, V and proconvertases 1/3 and 2 in plasma from patients with neuroendocrine tumours.
abstract: BACKGROUND
  Chromogranin (Cg) and secretogranin (Sg) are members of the granin family of proteins, which are expressed in neuroendocrine and nervous tissue. In recent publications we have presented generation of region-specific antibodies against CgA and CgB and also development of several region-specific radioimmunoassays for measurements of specific parts of the Cgs. In this study we describe generation of antibodies against SgII, SgIII, SgV and the proconvertases PC1/3 and PC2 and development of radioimmunoassays for measurements of these proteins.
  
  
  METHODS
  Peptides homologous to defined parts of the secretogranin and proconvertase molecules were selected and synthesised. Antibodies were raised, radioimmunoassays were developed and circulating levels of the proteins in plasma samples from 22 patients with neuroendocrine tumours were measured in the assays.
  
  
  RESULTS
  Increased plasma concentrations were recorded in 11, 4 and 3 of the patients with the SgII 154-165 (N-terminal secretoneurin), the SgII 172-186 (C-terminal Secretoneurin) and the SgII 225-242 assays respectively. The SgIII, SgV, PC1/3 and PC2 assays failed to detect increased concentrations in any of the patients.
  
  
  CONCLUSIONS
  Increased concentrations of SgII, especially the N-terminal part of secretoneurin could be measured in plasma from patients with endocrine pancreatic tumours and in this case this assay was quite comparable to measurements of CgA and CgB. Even though secretoneurin was not as frequently increased as CgA and CgB in patients with carcinoid tumours or pheochromocytoma it may be a useful marker for endocrine pancreatic tumours.
authors.affiliation: Department of Medical Sciences, Uppsala University Hospital, Uppsala, Sweden. mats.stridsberg@akademiska.se
authors.forename: Mats
authors.initials: M
authors.lastname: Stridsberg
authors.forename: Barbro
authors.initials: B
authors.lastname: Eriksson
authors.forename: Eva Tiensuu
authors.initials: ET
authors.lastname: Janson
mesh_terms: D053379:Chromogranin A / Q000097:blood; D053378:Chromogranin B / Q000097:blood; D002864:Chromogranins / Q000097:blood*; D006801:Humans; D051859:Neuroendocrine Secretory Protein 7B2 / Q000097:blood; D018358:Neuroendocrine Tumors / Q000097:blood*; D009479:Neuropeptides / Q000097:blood; D043484:Proprotein Convertases / Q000097:blood*; D011863:Radioimmunoassay; D053381:Secretogranin II / Q000097:blood
chemical_list: D053379:Chromogranin A; D053378:Chromogranin B; D002864:Chromogranins; D051859:Neuroendocrine Secretory Protein 7B2; D009479:Neuropeptides; C497678:SCG5 protein, human; D053381:Secretogranin II; C081159:secretoneurin; D043484:Proprotein Convertases