title: Immunosuppressive regulatory T cells are associated with aggressive breast cancer phenotypes: a potential therapeutic target.
abstract: FoxP3 is a marker for immunosuppressive CD25+CD4+ regulatory T cells. These regulatory T cells are thought to play a role in inducing immune tolerance to antigens and may be selectively recruited by carcinomas. We investigated whether breast carcinomas had significant numbers of FoxP3-positive regulatory T cells by immunohistochemistry, and if their presence was associated with other prognostic factors, such as Nottingham grade, hormone receptor immunohistochemical profile, tumor size, or lymph node metastases. Ninety-seven needle core or excisional breast biopsies with invasive breast carcinoma diagnosed at the University of Washington were stained with antibodies to FoxP3, estrogen receptor, and Her2/neu. The numbers of FoxP3-positive cells present within the neoplastic epithelium, and immediately adjacent stroma were counted manually in three high-powered fields (HPFs; x 400) by two independent pathologists. The average scores were then correlated with the parameters of interest. A threshold of >or=15 FoxP3-positive cells/HPF was used to define a FoxP3-positive case in some analyses. Higher average numbers of FoxP3-positive cells present significantly correlated with higher Nottingham grade status (P=0.000229). In addition, the presence of significant numbers (>or=15/HPF) of FoxP3-positive cells in breast carcinoma was positively associated with higher Nottingham grade (P=0.00002585). Higher average numbers of FoxP3-positive cells were also significantly associated with larger tumor size (>2.0 cm; P=0.012824) and trended toward an association with estrogen receptor negativity. Interestingly, 'triple-negative' (estrogen and progesterone receptor negative and Her2/neu negative) Nottingham grade III cases were also significantly associated with high numbers of FoxP3 cells. These results argue that regulatory T cells may play a role in inducing immune tolerance to higher grade, more aggressive breast carcinomas, and are a potential therapeutic target for these cancers.
authors.affiliation: Department of Anatomic Pathology, University of Washington Medical Center, Seattle, WA 98195-6100, USA.
authors.forename: Sandra D
authors.initials: SD
authors.lastname: Bohling
authors.forename: Kimberly H
authors.initials: KH
authors.lastname: Allison
mesh_terms: D001943:Breast Neoplasms / Q000276:immunology* / Q000473:pathology*; D005260:Female; D051858:Forkhead Transcription Factors / Q000276:immunology*; D006801:Humans; D007108:Immune Tolerance; D007150:Immunohistochemistry; D010641:Phenotype; D011379:Prognosis; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
chemical_list: C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors