title: Negligible nuclear FOXP3 expression in breast cancer epithelial cells compared with FOXP3-positive T cells.
abstract: BACKGROUND
  The presence of forkhead box protein 3 (FOXP3) in breast cancer cells is a matter of debate. We systematically analyzed expression of FOXP3 in 1574 breast carcinomas.
  
  
  METHODS
  For nuclear FOXP3 detection in epithelial breast cancer cells, tissue microarray technology was used. In addition, cultured breast cancer cell lines (ZR75-1, MCF7-WH, BT20, T47D, and SKBR3) were tested for FOXP3 expression using real-time polymerase chain reaction and flow cytometry for messenger RNA (mRNA) and protein quantification.
  
  
  RESULTS
  We could neither detect any significant levels of mRNA or protein expression of FOXP3 in human breast cancer cell lines, nor in breast cancer specimens. Weak nuclear staining for FOXP3 was detectable in 16 of 1574 breast cancer cases (1%) and was only seen in a small proportion of malignant cells. There was no difference in survival between patients with FOXP3-positive or -negative tumors.
  
  
  CONCLUSIONS
  FOXP3 does most likely not play a significant role in breast cancer biology, because it is only scarcely expressed in a very small proportion of breast cancer samples.
authors.affiliation: Institute of Pathology, University Hospital Basel, Basel, Switzerland.
authors.forename: Raoul A
authors.initials: RA
authors.lastname: Droeser
authors.forename: Ellen C
authors.initials: EC
authors.lastname: Obermann
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Wolf
authors.forename: Stephanie
authors.initials: S
authors.lastname: Wallner
authors.forename: Dominik
authors.initials: D
authors.lastname: Wolf
authors.forename: Alexandar
authors.initials: A
authors.lastname: Tzankov
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D018275:Carcinoma, Lobular / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism / Q000473:pathology; D004847:Epithelial Cells / Q000378:metabolism* / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D051858:Forkhead Transcription Factors / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007124:Immunoenzyme Techniques; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D009364:Neoplasm Recurrence, Local / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D009367:Neoplasm Staging; D011379:Prognosis; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013601:T-Lymphocytes / Q000378:metabolism* / Q000473:pathology; D014407:Tumor Cells, Cultured
chemical_list: D014408:Biomarkers, Tumor; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; D012333:RNA, Messenger
keywords: Breast cancer cell lines; Epithelial tumor cells; Forkhead Box Protein 3; Immunohistochemistry; Tissue microarray