title: Expression pattern of PLUNC proteins as an auxiliary tool for the diagnosis of high-grade mucoepidermoid carcinoma of the salivary gland.
abstract: BACKGROUND
  Mucoepidermoid carcinomas are the most frequent malignant neoplasia of the salivary glands and are histologically classified as low, intermediate, and high grade. At present, histochemical stains such as periodic acid-Schiff or mucicarmine are useful tools in making a diagnosis. Recently, expression of the PLUNC proteins has been described in mucin-producing salivary gland tumors, with the suggestion that they could provide a powerful tool for the diagnosis of difficult cases.
  
  
  METHODS
  This study evaluates the expression of PLUNC proteins in 30 cases of salivary gland mucoepidermoid carcinomas. Tumors were reviewed and classified according to histological grade. Periodic acid-Schiff, mucicarmine, and immunohistochemical staining for SPLUNC1, LPLUNC1, SPLUNC2, and LPLUNC2 were carried out. Immunostaining was classified as positive or negative.
  
  
  RESULTS
  The majority of the tumors (63%) were classified as low grade, 13% were intermediate grade, and 23% were high grade. SPLUNC1 (90%) and LPLUNC1 (93%) were positive in the majority of cases, mainly in mucous cells, mucin plugs, and intermediate cells. SPLUNC2 and LPLUNC2 did not present significative expression within the tumors; however, LPLUNC2 was found to stain positively in mast cells in 83% of the samples.
  
  
  CONCLUSIONS
  SPLUNC1 and LPLUNC1 showed a similar pattern of expression and could prove useful in the diagnosis of high-grade cases because of the differential staining in intermediate and epidermoid cells. The expression of LPLUNC2 in mast cells has not previously been reported, but further studies are necessary to validate this finding and to determine its significance.
authors.affiliation: Oral Diagnosis Department, Semiology and Oral Pathology, Piracicaba Dental School, State University of Campinas (UNICAMP), Piracicaba, Sao Paulo, Brazil.
authors.forename: Wilfredo A
authors.initials: WA
authors.lastname: González-Arriagada
authors.forename: Alan R
authors.initials: AR
authors.lastname: Santos-Silva
authors.forename: Fabio A
authors.initials: FA
authors.lastname: Ito
authors.forename: Pablo A
authors.initials: PA
authors.lastname: Vargas
authors.forename: Paul M
authors.initials: PM
authors.lastname: Speight
authors.forename: Lynne
authors.initials: L
authors.lastname: Bingle
authors.forename: Marcio A
authors.initials: MA
authors.lastname: Lopes
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001324:Autoantigens; D014408:Biomarkers, Tumor / Q000032:analysis*; D018277:Carcinoma, Mucoepidermoid / Q000175:diagnosis* / Q000473:pathology; D002329:Carmine / Q000032:analysis; D002648:Child; D002675:Child, Preschool; D050556:Fatty Acid-Binding Proteins; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics; D006023:Glycoproteins / Q000032:analysis*; D006801:Humans; D007150:Immunohistochemistry; D016350:Leucine Zippers / Q000235:genetics; D008297:Male; D008407:Mast Cells / Q000473:pathology; D008875:Middle Aged; D009077:Mucins / Q000032:analysis; D009092:Mucous Membrane / Q000473:pathology; D060787:Neoplasm Grading; D010750:Phosphoproteins / Q000032:analysis*; D011506:Proteins / Q000032:analysis; D012189:Retrospective Studies; D012468:Salivary Gland Neoplasms / Q000175:diagnosis* / Q000473:pathology; D012470:Salivary Glands, Minor / Q000473:pathology; D012471:Salivary Proteins and Peptides / Q000032:analysis; D055815:Young Adult
chemical_list: D001324:Autoantigens; C485599:BPIFA1 protein, human; C045623:BPIFA2 protein, human; C568077:BPIFB1 protein, human; D014408:Biomarkers, Tumor; D050556:Fatty Acid-Binding Proteins; D006023:Glycoproteins; D009077:Mucins; D010750:Phosphoproteins; D011506:Proteins; D012471:Salivary Proteins and Peptides; C029618:mucicarmine; D002329:Carmine