title: Detection of Epstein-Barr virus DNA in the peripheral-blood cells of patients with nasopharyngeal carcinoma: relationship to distant metastasis and survival.
abstract: OBJECTIVE
  Nasopharyngeal carcinoma (NPC) has been proved to be an Epstein-Barr virus (EBV)-associated cancer. By use of nested polymerase chain reactions (PCRs), we examined whether the presence of EBV DNA in the peripheral-blood cells (PBC) can serve as a prognostic indicator for NPC.
  
  
  METHODS
  Peripheral blood from 124 patients with NPC who had no evidence of distant metastasis and 114 healthy volunteers with serologically positive findings for EBV infection was collected prospectively. Plasma and erythrocytes were separated. DNA was extracted from PBCs and analyzed by a nested PCR using primers specific to Epstein-Barr virus nuclear antigen 1 (EBNA-1). All patients were treated by radiotherapy with or without chemotherapy. Clinical parameters and status of EBNA-1 in PBCs were used for survival analysis using the Kaplan-Meier method and the Cox proportional hazards model.
  
  
  RESULTS
  Positive rates of EBNA-1 DNA in PBCs of NPC patients and healthy volunteers are 71% and 14%, respectively (P =.001). No significant difference was observed with regard to the clinical characteristics of patients who were EBNA-1-positive (n = 88) and those who were EBNA-1-negative (n = 36). After a median follow-up period of 38 months (range, 24 to 56 months), 29 of 88 EBNA-1-positive patients and only one of 36 EBNA-1-negative patients developed distant metastases (P =.00015). Kaplan-Meier estimates of overall survival (P =.0010), metastasis-free survival (P =.0004), and progression-free survival (P =.0004) were significantly lower for the patients in the EBNA-1-positive group than for those in the EBNA-1-negative group. Multivariate Cox analysis confirmed the same results.
  
  
  CONCLUSIONS
  The presence of EBNA-1 DNA in PBCs is a novel, important risk factor for patients with NPC that indicates a significantly higher risk of developing distant metastasis as well as a lower survival rate.
authors.affiliation: Institute of Clinical Medicine, College of Medicine, and Department of Biochemistry and Center for Cellular and Molecular Biology, School of Life Science, National Yang-Ming University, Taipei, Taiwan.
authors.forename: J C
authors.initials: JC
authors.lastname: Lin
authors.forename: K Y
authors.initials: KY
authors.lastname: Chen
authors.forename: W Y
authors.initials: WY
authors.lastname: Wang
authors.forename: J S
authors.initials: JS
authors.lastname: Jan
authors.forename: W M
authors.initials: WM
authors.lastname: Liang
authors.forename: C S
authors.initials: CS
authors.lastname: Tsai
authors.forename: Y H
authors.initials: YH
authors.lastname: Wei
mesh_terms: D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D016022:Case-Control Studies; D002945:Cisplatin / Q000008:administration & dosage; D003131:Combined Modality Therapy; D004279:DNA, Viral / Q000097:blood*; D020031:Epstein-Barr Virus Infections / Q000097:blood / Q000150:complications*; D019309:Epstein-Barr Virus Nuclear Antigens / Q000302:isolation & purification*; D005260:Female; D005472:Fluorouracil / Q000008:administration & dosage; D006801:Humans; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000188:drug therapy / Q000401:mortality* / Q000473:pathology / Q000532:radiotherapy / Q000821:virology*; D009362:Neoplasm Metastasis; D016133:Polymerase Chain Reaction; D016016:Proportional Hazards Models; D016019:Survival Analysis
chemical_list: D004279:DNA, Viral; D019309:Epstein-Barr Virus Nuclear Antigens; C417029:EBV-encoded nuclear antigen 1; D002945:Cisplatin; D005472:Fluorouracil