title: Expression of PGP 9.5 in granular cell nerve sheath tumors: an immunohistochemical study of six cases.
abstract: BACKGROUND
  Protein gene product 9.5 (PGP 9.5) is expressed in brain at 20 to 50 times the levels detected in other organs. Immunohistochemical studies reveal this protein is localized to both central and peripheral neurons. Recently, PGP 9.5 is reported to be a useful marker for cellular neurothekeomas. Herein we test whether PGP 9.5 is a new marker for granular cell nerve sheath tumors.
  
  
  METHODS
  An immunohistochemical analysis for PGP 9.5 expression was carried out on all cases with the diagnosis of granular cell nerve sheath tumor seen over a 2-year period. In addition, we compared expression of PGP 9.5 with other accepted markers for neuroectodermal tumors including anti-S-100 protein and NKI/C3 monoclonal antibodies.
  
  
  RESULTS
  Six granular cell nerve sheath tumors were diagnosed in over 80,000 dermatopathology specimens in the two-year period. These cases were all positive for PGP 9.5 as well as for S-100 protein and NK1/C3.
  
  
  CONCLUSIONS
  These findings identify PGP 9.5 as a new immunohistochemical marker for use in the diagnosis of granular cell tumors. They also strengthen the histogenetic relationship between granular cell nerve sheath tumors and tumors of Schwann cell or perineurial origin.
authors.affiliation: Dermatopathology Section, Department of Dermatology, Boston University School of Medicine, Boston, Massachusetts, USA.
authors.forename: M
authors.initials: M
authors.lastname: Mahalingam
authors.forename: D
authors.initials: D
authors.lastname: LoPiccolo
authors.forename: H R
authors.initials: HR
authors.lastname: Byers
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis; D005260:Female; D016586:Granular Cell Tumor / Q000737:chemistry / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D018317:Nerve Sheath Neoplasms / Q000737:chemistry / Q000378:metabolism* / Q000473:pathology; D009418:S100 Proteins / Q000032:analysis; D012878:Skin Neoplasms / Q000737:chemistry / Q000378:metabolism* / Q000473:pathology; D013869:Thiolester Hydrolases / Q000032:analysis / Q000096:biosynthesis*; D043222:Ubiquitin Thiolesterase
chemical_list: D014408:Biomarkers, Tumor; D009418:S100 Proteins; D013869:Thiolester Hydrolases; D043222:Ubiquitin Thiolesterase