title: Expression of THOP1 and its relationship to prognosis in non-small cell lung cancer.
abstract: BACKGROUND
  The study was designed to detect the expression level of thimet oligopeptidase (THOP1) protein in non-small cell lung cancer (NSCLC) and investigate its correlation with clinicopathologic features and prognosis.
  
  
  METHODS
  Immunohistochemical staining was used to determine the expression of THOP1 protein in 120 NSCLC specimens and 53 distant normal lung tissues. Quantitative real-time PCR and western blotting were employed to measure the expression of THOP1 in 16 pairs of primary NSCLC and corresponding normal tissues.
  
  
  RESULTS
  Analysis of immunohistochemical staining suggested low THOP1 expression was found in 71 (59.2%) of the 120 NSCLC specimens and significantly correlated with positive lymph node metastasis (P = 0.048). However, low THOP1 expression was found in 22 (41.5%) of the 53 normal lung tissues. Chi-square test suggested that the expression of THOP1 was significantly higher in the normal lung tissues than that in the NSCLC specimens (P = 0.032). Real-Time PCR and western blotting showed that NSCLC specimens had decreased THOP1 mRNA and protein expression compared to corresponding normal tissues. Univariate analysis demonstrated that low THOP1 expression significantly predicted decreased 5-year disease-free survival (P = 0.038) and overall survival (P = 0.017). In addition, positive lymph node metastasis (P = 0.025) and advanced TNM stage (P = 0.009) significantly predicted decreased 5-year overall survival. However, multivariate Cox regression analysis showed that only low THOP1 expression retained its significance as an independent prognostic factor for unfavorable 5-year disease-free survival (P = 0.046) and overall survival (P = 0.021).
  
  
  CONCLUSIONS
  THOP1 may have clinical potentials to be employed as a promising biomarker to identify individuals with better prognosis and a novel antitumor agent for therapy of patients with NSCLC.
authors.affiliation: Department of Thoracic Surgery, Qi Lu Hospital, Shandong University, Jinan, Shandong Province, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Qi
authors.affiliation: Department of Thoracic Surgery, Qi Lu Hospital, Shandong University, Jinan, Shandong Province, China.
authors.forename: Shu-Hai
authors.initials: SH
authors.lastname: Li
authors.affiliation: Department of Thoracic Surgery, Qi Lu Hospital, Shandong University, Jinan, Shandong Province, China.
authors.forename: Li-Bo
authors.initials: LB
authors.lastname: Si
authors.affiliation: Department of Thoracic Surgery, Qi Lu Hospital, Shandong University, Jinan, Shandong Province, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Lu
authors.affiliation: Department of Thoracic Surgery, Qi Lu Hospital, Shandong University, Jinan, Shandong Province, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Tian
mesh_terms: D002289:Carcinoma, Non-Small-Cell Lung / Q000175:diagnosis* / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D045744:Cell Line, Tumor; D018572:Disease-Free Survival; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D008297:Male; D008666:Metalloendopeptidases / Q000235:genetics* / Q000378:metabolism*; D008875:Middle Aged; D012008:Recurrence
chemical_list: D008666:Metalloendopeptidases; C022510:thimet oligopeptidase