title: Immunohistochemical Expression of CD56and ALDH1in Common Salivary Gland Tumors.
abstract: BACKGROUND
  Natural killer (NK) cells, of which CD56is a specific marker, play an important role in host defense against tumors. Cancer stem cells, of which aldehyde dehydrogenase isoform 1 (ALDH1) is an immunohistochemical marker, are a group of tumorigenic cells which are involved in migration and tumor recurrences. We aimed to evaluate the expression of ALDH1and CD56in common salivary gland tumors, as well as their relationship with each other and with a number of clinicopathologic factors.
  
  
  METHODS
  Forty-five paraffin blocks of salivary gland tumors (pleomorphic adenoma, mucoepidermoid carcinoma and adenoid cystic carcinoma, 15 samples each) were selected. Malignant tumors were classified into two groups: low-grade (including mucoepidermoid carcinoma grade I) and high-grade (including mucoepidermoid carcinoma grade III and adenoid cystic carcinoma). Immunohistochemical staining for ALDH1and CD56markers was performed. Data were analyzed using SPSS (20) and the Chi-square test.
  
  
  RESULTS
  CD56expression was significantly higher in benign and high-grade malignant tumors (P=0.01). ALDH1overexpressed in all three salivary tumors, but not to statistically significant degree (P=0.54). There was no statistically significant correlation between ALDH1and CD56expression with demographic factors (age, gender, or location of tumor; P>0.05).
  
  
  CONCLUSIONS
  It appears that the number of NK cells and their function change in different types of salivary gland tumors (benign/malignant) and stroma. NK cells are important components of the anti-tumor system; therefore immune dysfunction is associated with tumor progression in tumors of the salivary gland. ALDH1overexpression suggests its role in tumorogenesis, but ALDH1is not involved in the morphogenesis of salivary gland tumors.
authors.affiliation: Department of Oral and Maxillofacial Pathology, School of Dentistry, Babol University of Medical Sciences, Babol, Iran.
authors.forename: Safoura
authors.initials: S
authors.lastname: Seifi
authors.affiliation: Department of Oral and Maxillofacial Pathology, School of Dentistry, Babol University of Medical Sciences, Babol, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Seyedmajidi
authors.affiliation: Dental Research Centre, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Jahanshah
authors.initials: J
authors.lastname: Salehinejad
authors.affiliation: Health Research Institute, Babol University of Medical Science, Mazandaran, Iran.
authors.forename: Hemmat
authors.initials: H
authors.lastname: Gholinia
authors.affiliation: Department of Oral and Maxillofacial Pathology, School of Dentistry, Babol University of Medical Sciences, Babol, Iran.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Aliakbarpour
keywords: ALDH1; Adenoid cystic carcinoma; CD56; Immunohistochemistry; Mucoepidermoid carcinoma; Pleomorphic adenoma