title: Young investigator challenge: The utility of GATA3 immunohistochemistry in the evaluation of metastatic breast carcinomas in malignant effusions.
abstract: BACKGROUND
  It is not uncommon to encounter challenges in the immunohistochemical confirmation of metastatic breast cancer given the limited sensitivities of mammaglobin and gross cystic disease fluid protein 15 (GCDFP-15/BRST-2) and the significant proportion of triple-negative breast carcinomas (ie, tumors that are negative for estrogen receptor [ER], and progesterone receptor [PgR], and human epidermal growth factor 2 [HER2]). GATA binding protein 3 (GATA3) has emerged as a potentially useful immunohistochemical adjunct during the evaluation of metastatic breast carcinomas in cytology specimens. The objective of the current study was to examine GATA3 expression in the context of malignant effusions secondary to both mammary and extramammary malignancies.
  
  
  METHODS
  In total, 306 malignant effusions (from 62 metastatic breast carcinomas and 244 extramammary malignancies) were examined using GATA3 immunohistochemistry. Effusions with metastatic breast carcinoma were also examined using immunohistochemistry for additional breast markers (ER, PgR, HER2, mammaglobin, and GCDFP-15/BRST-2).
  
  
  RESULTS
  GATA3 immunohistochemistry highlighted the tumor cells in 58 of the 62 samples (93.5%) from patients with metastatic breast carcinoma, which was higher than the observed sensitivity of immunohistochemistry for ER (63.8%), PgR (41.4%), HER2 (15.5%), mammaglobin (22.4%), and GCDFP-15/BRST-2 (5.2%). GATA3 expression also was observed in a subset of malignant effusions secondary to extramammary primaries, specifically, in 28 of 244 specimens (11.5%).
  
  
  CONCLUSIONS
  GATA3 is a highly sensitive marker for the detection of metastatic breast carcinomas in effusion specimens. However, this marker is not entirely specific for malignancies of breast origin. Thus, GATA3 should be used in conjunction with additional immunohistochemical markers during the cytologic evaluation of malignant effusions.
authors.affiliation: Department of Pathology, University of Michigan Health System, Ann Arbor, Michigan.
authors.forename: Madelyn
authors.initials: M
authors.lastname: Lew
authors.affiliation: Department of Pathology, University of Michigan Health System, Ann Arbor, Michigan.
authors.forename: Judy C
authors.initials: JC
authors.lastname: Pang
authors.affiliation: Department of Pathology, University of Michigan Health System, Ann Arbor, Michigan.
authors.forename: Xin
authors.initials: X
authors.lastname: Jing
authors.affiliation: Department of Pathology, University of Michigan Health System, Ann Arbor, Michigan.
authors.forename: Kristina L
authors.initials: KL
authors.lastname: Fields
authors.affiliation: Department of Pathology, University of Michigan Health System, Ann Arbor, Michigan.
authors.forename: Michael H
authors.initials: MH
authors.lastname: Roh
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000378:metabolism / Q000556:secondary*; D014408:Biomarkers, Tumor / Q000378:metabolism*; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000378:metabolism / Q000556:secondary*; D018275:Carcinoma, Lobular / Q000378:metabolism / Q000556:secondary*; D005260:Female; D005500:Follow-Up Studies; D050990:GATA3 Transcription Factor / Q000378:metabolism*; D006801:Humans; D007124:Immunoenzyme Techniques; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D016066:Pleural Effusion, Malignant / Q000378:metabolism / Q000473:pathology*; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D012108:Research Personnel
chemical_list: D014408:Biomarkers, Tumor; D050990:GATA3 Transcription Factor; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C494749:GATA3 protein, human; C508053:ERBB2 protein, human
keywords: GATA3; breast; cancer; carcinoma; cytology; immunohistochemistry; malignant effusion