title: PLAG1: An Immunohistochemical Marker with Limited Utility in Separating Pleomorphic Adenoma from Other Basaloid Salivary Gland Tumors.
abstract: OBJECTIVE
  Fine-needle aspiration (FNA) diagnosis of salivary gland neoplasms is often challenging. Differentiating between pleomorphic adenomas (PA) and other basaloid neoplasms, especially basal cell adenoma (BCA) and adenoid cystic carcinoma (AdCC), can be difficult in cellular aspirates. PLAG1 (PA gene 1) is a proto-oncogene, which is frequently rearranged in PAs, leading to the aberrant expression of its protein. PLAG1 IHC expression has been reported to be positive in most PAs. The aim of this study was to evaluate the sensitivity and specificity of PLAG1 to differentiate PA from other basaloid neoplasms.
  
  
  METHODS
  Immunohistochemical evaluation of PLAG1 was performed on 125 cases (52 FNAs and 73 surgical excisions). Nuclear staining of tumor cells was scored by the intensity and percentage of positive tumor cells. A combined score of >5 was defined as positive.
  
  
  CONCLUSIONS
  The sensitivity (55%) and specificity (75%) of PLAG1 in diagnosing PA in FNAs is relatively modest thus limiting its diagnostic utility. BCAs and AdCCs showed PLAG1 false positivity, in surgical excision specimens and less so in FNAs. This may be due to limited sampling or tumor heterogeneity. Hence, PLAG1 is a modest marker for PAs in FNAs.
authors.affiliation: Department of Pathology and Laboratory Medicine, Emory University Hospital, Atlanta, Ga., USA.
authors.forename: Vaidehi
authors.initials: V
authors.lastname: Avadhani
authors.forename: Cynthia
authors.initials: C
authors.lastname: Cohen
authors.forename: Momin T
authors.initials: MT
authors.lastname: Siddiqui
mesh_terms: D008949:Adenoma, Pleomorphic / Q000175:diagnosis* / Q000378:metabolism* / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism*; D003528:Carcinoma, Adenoid Cystic / Q000175:diagnosis / Q000378:metabolism / Q000473:pathology; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D008875:Middle Aged; D000090063:Proto-Oncogene Mas; D012189:Retrospective Studies; D012468:Salivary Gland Neoplasms / Q000175:diagnosis* / Q000378:metabolism* / Q000473:pathology; D012469:Salivary Glands / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; D004268:DNA-Binding Proteins; C000715470:MAS1 protein, human; C104382:PLAG1 protein, human; D000090063:Proto-Oncogene Mas