title: GATA-3 expression as a predictor of hormone response in breast cancer.
abstract: BACKGROUND
  Expression of estrogen receptor-alpha (ERalpha) as determined by immunohistochemistry of tumor tissue is currently the most clinically useful test to predict hormone responsiveness of breast cancer. Thirty percent of ERalpha-positive breast cancers do not respond to hormonal therapy. GATA-3 is a transcription factor that is expressed in association with ERalpha and there is evidence that GATA factors influence response to estrogen. In this pilot study, we investigated whether GATA-3 expression is associated with hormone response in breast cancer.
  
  
  METHODS
  Breast cancer tissue was stained for GATA-3 expression by immunohistochemistry in ERalpha-positive cancers from 28 patients, 14 of whom were defined as hormone unresponsive (cases) and 14 of whom were age-matched controls with hormone-responsive, ERalpha-positive cancers (controls).
  
  
  RESULTS
  Comparing cases and controls, there were no differences in expression of ERalpha; progesterone receptor, ErbB2; or tumor grade. Using 20% nuclear staining to characterize tumors as GATA-3 positive or GATA-3 negative, 6 of 14 (43%) cancers in the hormone-unresponsive group and none of the controls were classified as GATA-3 negative (odds ratio, 8.2; 95% confidence interval, 1.2-infinity; p = 0.031). Using different cut points to characterize GATA-3 positivity yielded very similar results, indicating a positive association between lack of GATA-3 expression and lack of response to hormonal therapy.
  
  
  CONCLUSIONS
  The study suggests that analyzing ERalpha-positive breast tumors for GATA-3 using immunohistochemistry might improve prediction of hormone responsiveness. The association between GATA-3 expression and hormone response suggests that GATA-3 may play a role in mechanisms controlling response to estrogen.
authors.affiliation: Department of Surgery, Thomas Jefferson University, Philadelphia, PA, USA.
authors.forename: Purvi
authors.initials: P
authors.lastname: Parikh
authors.forename: Juan P
authors.initials: JP
authors.lastname: Palazzo
authors.forename: Lewis J
authors.initials: LJ
authors.lastname: Rose
authors.forename: Constantine
authors.initials: C
authors.lastname: Daskalakis
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Weigel
mesh_terms: D000328:Adult; D000368:Aged; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy / Q000378:metabolism*; D016022:Case-Control Studies; D005260:Female; D050990:GATA3 Transcription Factor; D006801:Humans; D007150:Immunohistochemistry; D016015:Logistic Models; D008875:Middle Aged; D010865:Pilot Projects; D011237:Predictive Value of Tests; D013194:Staining and Labeling; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D018931:Antineoplastic Agents, Hormonal; D050990:GATA3 Transcription Factor; C494749:GATA3 protein, human; D014157:Transcription Factors