title: Prognostic impact of pretherapeutic gamma-glutamyltransferase on patients with nasopharyngeal carcinoma.
abstract: BACKGROUND
  Gamma-glutamyltransferase (GGT) is a membrane-bound enzyme involved in the metabolism of glutathione. Studies suggested that GGT played an important role in the tumor development, progression, invasion and drug resistance and prognosis. The association between GGT and prognosis of patients with nasopharyngeal carcinoma (NPC) was unknown. This study was conducted to investigate the association of pretherapeutic serum level of GGT with clinical-pathological parameters and survival in patients with NPC.
  
  
  METHODS
  Two hundred and twenty-two patients with NPC were recruited in this study and were stratified into two GGT risk groups (≤ 34.5 U/L, > 34.5 U/L). The association of pretherapeutic serum GGT levels with clinical-pathological parameters was examined. Univariate and multivariate survival analyses were performed.
  
  
  RESULTS
  The pretherapeutic serum level of GGT was not associated with gender, age, pathology, T stage, N stage, TNM stage, chemotherapy or radiotherapy in patients with NPC. Patients in the high-risk GGT group had a poorer survival than the low-risk GGT group (3-year overall survival, 74.2% vs. 50.2%, P = 0.001; 3-year progression-free survival, 76.4% vs. 47.1%, P < 0.001; 3-year loco-regional relapse-free survival, 76.4% vs. 51.3%, P < 0.001; 3-year distant metastasis-free survival, 89.5% vs. 66.4%, P < 0.001). Multivariate analysis suggested that patients in the high-risk GGT group had 2.117 (95% confidence interval [CI], 1.225 ∼ 3.659, P = 0.007) times the risk of death, 2.836 (95% CI, 1.765 ∼ 4.557, P < 0.001) times the risk of progression, 2.551 (95% CI, 1.573 ∼ 4.138, P < 0.001) times the risk of relapse, and 3.331 (95% CI, 1.676 ∼ 6.622, P < 0.001) times the risk of metastasis compared with those in the low-risk GGT group.
  
  
  CONCLUSIONS
  The pretherapeutic serum level of GGT might serve as a novel independent prognostic factor for overall-survival, progression-free survival, loco-regional relapse-free survival and distant metastasis-free survival in patients with NPC.
authors.affiliation: Department of Radiotherapy, Cancer Center of Guangzhou Medical University, Guangdong, China.
authors.forename: Yue-Feng
authors.initials: YF
authors.lastname: Wen
authors.affiliation: Guangzhou Institute of Oncology, Cancer Center of Guangzhou Medical University, Guangdong, China.
authors.forename: Xian-Zi
authors.initials: XZ
authors.lastname: Yang
authors.affiliation: Guangzhou Institute of Oncology, Cancer Center of Guangzhou Medical University, Guangdong, China.
authors.forename: Li-Si
authors.initials: LS
authors.lastname: Zeng
authors.affiliation: Department of Radiotherapy, Cancer Center of Guangzhou Medical University, Guangdong, China.
authors.forename: Hai-Hua
authors.initials: HH
authors.lastname: Peng
authors.affiliation: Department of Radiotherapy, Cancer Center of Guangzhou Medical University, Guangdong, China.
authors.forename: Wen-Jin
authors.initials: WJ
authors.lastname: Huang
authors.affiliation: Department of Radiotherapy, Cancer Center of Guangzhou Medical University, Guangdong, China.
authors.forename: Long-Mei
authors.initials: LM
authors.lastname: Cai
authors.affiliation: Department of Radiotherapy, Cancer Center of Guangzhou Medical University, Guangdong, China.
authors.forename: Tong-Chong
authors.initials: TC
authors.lastname: Zhou
authors.affiliation: Department of Radiotherapy, Cancer Center of Guangzhou Medical University, Guangdong, China.
authors.forename: Xiao-Dan
authors.identifier: http://orcid.org/0000-0001-5784-9425
authors.initials: XD
authors.lastname: Lin
mesh_terms: D000328:Adult; D002277:Carcinoma / Q000175:diagnosis* / Q000201:enzymology; D018450:Disease Progression; D018572:Disease-Free Survival; D019008:Drug Resistance, Neoplasm; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000201:enzymology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000175:diagnosis* / Q000201:enzymology; D009362:Neoplasm Metastasis; D009364:Neoplasm Recurrence, Local / Q000473:pathology; D011379:Prognosis; D012372:ROC Curve; D016896:Treatment Outcome; D005723:gamma-Glutamyltransferase / Q000097:blood*
chemical_list: D005723:gamma-Glutamyltransferase