title: Expression of sodium iodide symporter in human breast tissues.
abstract: OBJECTIVE
  Sodium iodide symporter (NIS) expression in breast cancer (BC) tissues suggests the possibility of using radioiodine for diagnostic and therapeutic purposes. This study evaluated NIS protein expression in primary BC samples and its association with BC prognostic markers and thyroid functional parameters.
  
  
  METHODS
  Fifty-six breast tissue samples from 52 operated women (41 BC, 11 benign breast diseases (BBD) and 4 peritumoral adjacent to the carcinoma tissues samples) were analyzed by immunohistochemistry using monoclonal anti-NIS antibody. Measurements of baseline levels of thyroid hormones and antibodies were also analysed in association with NIS protein expression.
  
  
  RESULTS
  NIS presented positive cytoplasmic immunoreactivity in the majority of BBD samples (45% ) and in 3 out of 4 breast tissues adjacent to carcinoma. Immunoreactivity was extremely faint in BC samples. Mean thyroid hormones levels and thyroid antibodies positivity did not differ statistically between patients with NIS positive (faint expression) and NIS negative BC. NIS expression appeared to be independent of estrogen (ER) and progesterone receptor (PR) expression as well as of lymph node status.
  
  
  CONCLUSIONS
  BC samples expressed only faintly and mainly cytoplasmic NIS protein, suggesting the presence of a non-functional NIS protein. The hypothesis of the downregulation of NIS expression during carcinogenesis cannot be excluded.
authors.affiliation: 1st Department of Internal Medicine, "Laiko" General Hospital, University of Athens Medical School, Athens, Greece.
authors.forename: Anna
authors.initials: A
authors.lastname: Angelousi
authors.forename: Afrodite
authors.initials: A
authors.lastname: Nonni
authors.forename: Eva
authors.initials: E
authors.lastname: Kassi
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Kontzoglou
mesh_terms: D000328:Adult; D001940:Breast / Q000737:chemistry; D001943:Breast Neoplasms / Q000737:chemistry* / Q000503:physiopathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D011379:Prognosis; D027981:Symporters / Q000032:analysis*; D013961:Thyroid Gland / Q000503:physiopathology; D000099209:Sodium-Iodide Symporters
chemical_list: D027981:Symporters; D000099209:Sodium-Iodide Symporters