title: Localization of proinsulin and insulin in human insulinoma: preliminary immunohistochemical results.
abstract: We have carried out an immunohistochemical investigation of 15 human insulinomas applying monoclonal antibodies specifically recognizing proinsulin and insulin. Our results demonstrate that the epitopes unique to proinsulin and insulin can be detected with the respective monoclonal antibodies using the protein A-gold technique after routine formaldehyde fixation and paraffin embedding of the tissues. The immunostaining pattern for proinsulin and insulin in the insulinomas was different from the observed in B cells of pancreatic islets present in the adjacent normal pancreas. Furthermore, the pattern of immunostaining was found to vary from tumor to tumor. These findings strongly suggest the possibility of a disturbed proinsulin to insulin conversion in human insulinomas.
authors.affiliation: Interdepartmental Electron Microscopy, University of Basel, Switzerland.
authors.forename: J
authors.initials: J
authors.lastname: Roth
authors.forename: M
authors.initials: M
authors.lastname: Kasper
authors.forename: B
authors.initials: B
authors.lastname: Stamm
authors.forename: W H
authors.initials: WH
authors.lastname: Häcki
authors.forename: M J
authors.initials: MJ
authors.lastname: Storch
authors.forename: O D
authors.initials: OD
authors.lastname: Madsen
authors.forename: G
authors.initials: G
authors.lastname: Klöppel
authors.forename: P U
authors.initials: PU
authors.lastname: Heitz
mesh_terms: D007516:Adenoma, Islet Cell / Q000032:analysis*; D006801:Humans; D007150:Immunohistochemistry; D007328:Insulin / Q000032:analysis*; D007340:Insulinoma / Q000032:analysis*; D010190:Pancreatic Neoplasms / Q000032:analysis*; D011384:Proinsulin / Q000032:analysis*
chemical_list: D007328:Insulin; D011384:Proinsulin