title: Dickkopf-1 expression is a novel prognostic marker for gastric cancer.
abstract: OBJECTIVE
  To investigate the involvement of Dickkopf-1 expression in gastric cancer.
  
  
  METHODS
  Dickkopf-1 mRNA and protein expression were determined by real-time quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) and immunohistochemistry in specimens of primary cancer and their adjacent noncancerous tissues in gastric cancer patients.
  
  
  RESULTS
  Dickkopf-1 mRNA and protein expression levels were both significantly upregulated in gastric cancer lesions compared with adjacent noncancerous tissues. Its positive expression was correlated with depth of invasion, vessel invasion, lymph node and distant metastasis, and TNM stage of tumors. Additionally, in stages I, II, and III gastric cancers, the 5- year survival rate of patients with a high expression of Dickkopf-1 was significantly lower than that in patients with low expression. In stage IV, Dickkopf-1 expression did not correlate with the 5-year survival rate. Further multivariate analysis suggested that the up-regulation of Dickkopf-1 was an independent prognostic indicator for gastric cancer.
  
  
  CONCLUSIONS
  A subset of cases with gastric cancer revealed the up-regulation of Dickkopf-1, which was associated with a progressive pathological feature and an aggressive clinical course. Therefore, Dickkopf-1 expression may be predictor for poor prognosis in patients with gastric cancer. This is the first report describing the involvement of Dickkopf-1 in gastric cancer.
authors.affiliation: Department of Gastroenterology, Huai'an No.1 Hospital, Nanjing Medical University, Huai'an, Jiangsu, China. gao.jsha@gmail.com
authors.forename: Chengcheng
authors.initials: C
authors.lastname: Gao
authors.forename: Rui
authors.initials: R
authors.lastname: Xie
authors.forename: Chengcheng
authors.initials: C
authors.lastname: Ren
authors.forename: Xiaozhong
authors.initials: X
authors.lastname: Yang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000096:biosynthesis* / Q000235:genetics; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D036341:Intercellular Signaling Peptides and Proteins / Q000096:biosynthesis* / Q000235:genetics; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D011379:Prognosis; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology
chemical_list: D014408:Biomarkers, Tumor; C501126:DKK1 protein, human; D036341:Intercellular Signaling Peptides and Proteins; D012333:RNA, Messenger