title: Interleukin-17-producing cell infiltration in the breast cancer tumour microenvironment is a poor prognostic factor.
abstract: OBJECTIVE
  Interleukin-17 (IL-17) is a proinflammatory cytokine that is most prominently produced by T-helper type 17 (Th17) cells, a distinct CD4+ T-helper cell subset. The aim of this study was to investigate the level of IL-17-producing cells in the breast cancer tumour microenvironment and its prognostic role.
  
  
  RESULTS
  A total of 207 breast carcinoma specimens were assessed by IL-17 immunohistochemistry, and the findings were correlated with clinicopathological parameters. We found that increased numbers of IL-17-producing cells were correlated with high histological grade, negative ER/PR status, and triple-negative molecular subtypes segregated by immunoprofiles. However, they did not correlate with stage, tumour size, nodal status, HER2 status, or histological type. Patients with tumours with high numbers of IL-17-producing cells had shorter disease-free survival (DFS) than patients with tumours with low numbers of IL-17-producing cells (P < 0.01). In multivariate analysis, high IL-17 level [hazard ratio (HR) 2.24; 95% CI 1.06-4.75], advanced T stage (HR 2.73; 95% CI 1.30-5.73), positive HER2 status (HR 4.88; 95% CI 1.47-16.18) and triple-negative subtype (HR 7.46; 95% CI 1.38-40.36) were significant prognostic factors for DFS.
  
  
  CONCLUSIONS
  Our results indicate that a high level of IL-17-producing cells in the breast cancer tumour microenvironment is a poor prognostic factor.
authors.affiliation: Department of Pathology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Wen-Chung
authors.initials: WC
authors.lastname: Chen
authors.forename: Yu-Hsuan
authors.initials: YH
authors.lastname: Lai
authors.forename: Hung-Yu
authors.initials: HY
authors.lastname: Chen
authors.forename: How-Ran
authors.initials: HR
authors.lastname: Guo
authors.forename: Ih-Jen
authors.initials: IJ
authors.lastname: Su
authors.forename: Helen H W
authors.initials: HH
authors.lastname: Chen
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000276:immunology* / Q000473:pathology*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D020381:Interleukin-17 / Q000096:biosynthesis*; D053208:Kaplan-Meier Estimate; D016246:Lymphocytes, Tumor-Infiltrating / Q000276:immunology* / Q000473:pathology*; D008875:Middle Aged; D015999:Multivariate Analysis; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D058504:Th17 Cells / Q000276:immunology* / Q000473:pathology*; D059016:Tumor Microenvironment / Q000276:immunology; D055815:Young Adult
chemical_list: D020381:Interleukin-17; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C508053:ERBB2 protein, human
keywords: breast cancer; inflammation; interleukin-17; prognosis; tumour microenvironment