title: Salivary gland-like tumors of the breast express basal-type immunohistochemical markers.
abstract: BACKGROUND
  Salivary gland-like tumors represent approximately 2% of primary breast carcinomas. These special histologic subtypes are characteristically negative for ER, PR, and HER2 (triple negative), and include adenoid cystic carcinoma, mucoepidermoid carcinoma, acinic cell carcinoma, and polymorphous low-grade adenocarcinoma. Approximately 75% of triple-negative breast carcinomas belong to the basal-like subtype by gene expression profiling. Immunohistochemical panels that include basal-like markers such as EGFR, CK5/6, p-cadherin, p63, and c-kit provide useful surrogates to gene expression arrays for classification of triple-negative breast cancers into the basal-like subtype. The purpose of this study was to explore the expression of these markers in salivary gland-like tumors of the breast.
  
  
  METHODS
  Excisional specimens from 10 untreated invasive triple-negative mammary carcinomas with salivary gland-like morphologies were evaluated for the immunohistochemical expression of EGFR, CK5/6, p-cadherin, p63, and c-kit using formalin-fixed, paraffin-embedded tissue and the L-SAB detection method.
  
  
  RESULTS
  On the basis of morphology, 5 carcinomas were classified as adenoid cystic, 3 as mucoepidermoid, and 2 as polymorphous low grade. All of the adenoid cystic carcinomas, mucoepidermoid carcinomas, and polymorphous low-grade adenocarcinomas showed strong and diffuse expression of CK5/6, p-cadherin, and p63. EGFR was expressed weakly in adenoid cystic carcinomas and polymorphous low grade, whereas mucoepidermoid carcinomas had a stronger expression. C-kit was expressed in adenoid cystic carcinomas and low-grade polymorphous, but only weakly positive in mucoepidermoid carcinomas.
  
  
  CONCLUSIONS
  Adenoid cystic, mucoepidermoid, and polymorphous low-grade carcinomas of the breast express immunohistochemical markers that characterize the intrinsic basal-like subtype of breast cancer.
authors.affiliation: Department of Pathology, University of Miami Miller School of Medicine, Jackson Memorial Hospital and Sylvester Cancer Center, Miami, FL, USA. reyesm@mskcc.org
authors.forename: Carolina
authors.initials: C
authors.lastname: Reyes
authors.forename: Merce
authors.initials: M
authors.lastname: Jorda
authors.forename: Carmen
authors.initials: C
authors.lastname: Gomez-Fernández
mesh_terms: D014408:Biomarkers, Tumor / Q000235:genetics* / Q000378:metabolism; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D018295:Neoplasms, Basal Cell / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D012469:Salivary Glands / Q000473:pathology*; D064726:Triple Negative Breast Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*
chemical_list: D014408:Biomarkers, Tumor