title: Serum CXCL9 levels are associated with tumor progression and treatment outcome in patients with nasopharyngeal carcinoma.
abstract: OBJECTIVE
  The aim of this cohort study was to examine the role of the chemokine (C-X-C motif) ligand 9 (CXCL9) on nasopharyngeal carcinoma (NPC).
  
  
  METHODS
  Sera from 205 NPC patients and 231 healthy individuals, and 86 NPC tumor samples were enrolled. CXCL9 expression in tissue samples was analyzed by quantitative real-time PCR and immunohistochemistry. CXCL9 serum concentrations were measured by enzyme-linked immunosorbent assay.
  
  
  RESULTS
  CXCL9 expression was significantly higher in tumors than in normal epithelium. CXCL9 serum concentrations were also significantly higher in NPC patients compared to those in healthy individuals (516.8±617.6 vs. 170.7±375.0 pg/mL, P<0.0001). Serum CXCL9 levels were significantly higher in NPC patients with higher tumor stages, nodal stages, and overall stages (P<0.001, P = 0.001, and P<0.001, respectively). We found a statistically significant correlation between the concentrations of CXCL9 and EBV DNA load in the NPC patients (Spearman's correlation analysis; r = 0.473, P<0.001; 95% confidence interval, 0.346-0.582). Moreover, NPC patients with higher CXCL9 levels (>290 pg/mL, median) before treatment had worse prognoses for overall survival and disease-free survival (P = 0.045 and P = 0.008, respectively). Multivariate logistic regression analyses also indicated that higher CXCL9 serum levels were an independent prognostic factor for disease-free survival (P = 0.015).
  
  
  CONCLUSIONS
  Our study demonstrated that CXCL9 is associated with tumor burden and aggressiveness of NPC tumors and the serum level of this ligand may be useful as a prognostic indicator.
authors.affiliation: Department of Otolaryngology-Head & Neck Surgery, Chang Gung Memorial Hospital at Lin-Kou, Tao-Yuan, Taiwan.
authors.forename: Li-Jen
authors.initials: LJ
authors.lastname: Hsin
authors.forename: Huang-Kai
authors.initials: HK
authors.lastname: Kao
authors.forename: I-How
authors.initials: IH
authors.lastname: Chen
authors.forename: Ngan-Ming
authors.initials: NM
authors.lastname: Tsang
authors.forename: Cheng-Lung
authors.initials: CL
authors.lastname: Hsu
authors.forename: Shiau-Chin
authors.initials: SC
authors.lastname: Liu
authors.forename: Yu-Sun
authors.initials: YS
authors.lastname: Chang
authors.forename: Kai-Ping
authors.initials: KP
authors.lastname: Chang
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D054370:Chemokine CXCL9 / Q000097:blood*; D004279:DNA, Viral / Q000097:blood; D018450:Disease Progression; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D004854:Herpesvirus 4, Human / Q000302:isolation & purification; D006801:Humans; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000097:blood* / Q000473:pathology / Q000628:therapy; D060888:Real-Time Polymerase Chain Reaction; D016896:Treatment Outcome; D019562:Viral Load
chemical_list: C080810:CXCL9 protein, human; D054370:Chemokine CXCL9; D004279:DNA, Viral