title: Serine protease inhibitor 8 is a novel immunohistochemical marker for neuroendocrine tumors of the pancreas.
abstract: OBJECTIVE
  The intracellular serine protease inhibitor 8 (SERPINB8) is expressed by squamous epithelium, monocytes, and a subset of neuroendocrine cells. Using immunohistochemistry, we now have further investigated the expression of SERPINB8 in normal neuroendocrine cells and its potential use as a marker to identify neuroendocrine tumors of the pancreas.
  
  
  RESULTS
  In normal neuroendocrine tissues, strongest SERPINB8 expression was detected in islets of Langerhans of the pancreas. Moderate SERPINB8 expression was observed in neuroendocrine cells of the thyroid, adrenal cortex, colon, and pituitary gland. Fluorescent double staining revealed that in the pancreas, SERPINB8 is specifically expressed by insulin-producing beta cells. In a panel of 20 patients with pancreatic islet cell tumors, however, SERPINB8 was broadly expressed and not restricted to insulinomas. In islet cell tumors, SERPINB8 had a similar diagnostic sensitivity as compared with the widely used neuroendocrine markers chromogranin A and synaptophysin. When SERPINB8 was combined with these 2 markers, an even higher diagnostic sensitivity was reached. In contrast, exocrine adenocarcinomas of the pancreas showed no SERPINB8 expression.
  
  
  CONCLUSIONS
  The SERPINB8 is expressed in normal neuroendocrine cells of several organs as well as in neuroendocrine tumors of the pancreas, where it can be used as an additional diagnostic immunohistochemical marker.
authors.affiliation: Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Pieter J A
authors.initials: PJ
authors.lastname: de Koning
authors.forename: Niels
authors.initials: N
authors.lastname: Bovenschen
authors.forename: Roel
authors.initials: R
authors.lastname: Broekhuizen
authors.forename: Cornelis J M
authors.initials: CJ
authors.lastname: Lips
authors.forename: J Alain
authors.initials: JA
authors.lastname: Kummer
mesh_terms: D000302:Adrenal Cortex / Q000166:cytology / Q000378:metabolism; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis*; D002116:Calcitonin / Q000032:analysis; D002648:Child; D002675:Child, Preschool; D053379:Chromogranin A / Q000032:analysis; D003106:Colon / Q000166:cytology / Q000378:metabolism; D005260:Female; D005934:Glucagon / Q000032:analysis; D006801:Humans; D007150:Immunohistochemistry; D007328:Insulin / Q000032:analysis; D050417:Insulin-Secreting Cells / Q000166:cytology / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D055099:Neuroendocrine Cells / Q000166:cytology / Q000378:metabolism; D018358:Neuroendocrine Tumors / Q000378:metabolism* / Q000473:pathology; D010190:Pancreatic Neoplasms / Q000378:metabolism* / Q000473:pathology; D010902:Pituitary Gland / Q000166:cytology / Q000378:metabolism; D015843:Serpins / Q000032:analysis*; D016708:Synaptophysin / Q000032:analysis; D013961:Thyroid Gland / Q000166:cytology / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; D053379:Chromogranin A; D007328:Insulin; C108403:SERPINB8 protein, human; D015843:Serpins; D016708:Synaptophysin; D002116:Calcitonin; D005934:Glucagon