title: Elevated plasma big ET-1 is associated with distant failure in patients with advanced-stage nasopharyngeal carcinoma.
abstract: BACKGROUND
  Endothelin-1 (ET-1) is a potent vasoactive peptide and a hypoxia-inducible angiogenic growth factor associated with the development and spread of solid tumors. The clinical significance of plasma big ET-1 in patients with advanced-stage nasopharyngeal carcinoma (NPC) is not known.
  
  
  METHODS
  Pretreatment plasma big ET-1 levels were measured in 62 patients with advanced-stage NPC using a sandwich enzyme-linked immunoassay and compared with the levels from a control group (n = 19 participants).
  
  
  RESULTS
  The median pretreatment plasma big ET-1 level in patients with advanced-stage NPC was 4.6 pg/mL (range, 1.9-15.2 pg/mL) and was significantly elevated compared with median plasma big ET-1 levels in healthy controls, 2.6 pg/mL (1.6-4.5 pg/mL) (P < .001). Using the upper limit (4.5 pg/mL) of control subjects as the cut-off value, plasma big ET-1 was < or = 4.5 pg/mL in 29 (46.8%) patients and > 4.5 pg/mL in 33 (53.2%) patients. A pretreatment plasma big ET-1 level > 4.5 pg/mL was associated with a significantly poorer 2-year distant metastasis-free survival rate (56.7% vs. 81.1%, P = .031). Multivariate analysis showed that N classification (hazard ratio [HR], 2.416; 95% confidence interval [CI], 1.071-5.447; P = .034) and pretreatment plasma big ET-1 level (HR, 3.151; 95% CI, 1.099-9.028, P = .033) were independent significant prognostic factors for posttreatment distant failure in patients with advanced-stage NPC.
  
  
  CONCLUSIONS
  Pretreatment plasma big ET-1 levels may be useful in predicting posttreatment distant failure in patients with advanced-stage NPC.
authors.affiliation: State Key Laboratory of Oncology in Southern China, Cancer Center, Sun Yat-Sen University, Guangzhou.
authors.forename: Hai-Qiang
authors.initials: HQ
authors.lastname: Mai
authors.forename: Zong-Yuan
authors.initials: ZY
authors.lastname: Zeng
authors.forename: Chang-Qing
authors.initials: CQ
authors.lastname: Zhang
authors.forename: Kai-Tao
authors.initials: KT
authors.lastname: Feng
authors.forename: Xiang
authors.initials: X
authors.lastname: Guo
authors.forename: Hao-Yuan
authors.initials: HY
authors.lastname: Mo
authors.forename: Man-Quan
authors.initials: MQ
authors.lastname: Deng
authors.forename: Hua-Qing
authors.initials: HQ
authors.lastname: Min
authors.forename: Ming-Huang
authors.initials: MH
authors.lastname: Hong
mesh_terms: D000328:Adult; D014408:Biomarkers, Tumor / Q000097:blood*; D002277:Carcinoma / Q000473:pathology*; D016022:Case-Control Studies; D019332:Endothelin-1 / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009303:Nasopharyngeal Neoplasms / Q000473:pathology*; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D011379:Prognosis; D016019:Survival Analysis; D016896:Treatment Outcome
chemical_list: D014408:Biomarkers, Tumor; D019332:Endothelin-1