title: Positive association between CD44 gene rs13347 C>T polymorphism and risk of cancer in Asians: a systemic review and meta-analysis.
abstract: BACKGROUND
  Cluster of differentiation 44 (CD44) is an important surface marker of cancer stem cells in a variety of tumors. A number of previous studies have been conducted to investigate the association between CD44 gene rs13347 C>T polymorphism and cancer risk in humans; nevertheless, the results remain controversial. We therefore performed this meta-analysis to confirm the role of this polymorphism in susceptibility to human cancer.
  
  
  METHODS
  The studies published up to December 2015 were searched in PubMed, Web of Science, and China National Knowledge Infrastructure databases. Twelve eligible case-control studies were identified, involving a total of 6,982 cases and 7,430 controls. Pooled odds ratio (OR) and corresponding 95% confidence interval (CI) were calculated using a fixed or random-effect model to estimate the strength of the association.
  
  
  RESULTS
  The results of the overall analyses indicated that CD44 gene rs13347 polymorphism was significantly associated with cancer risk in Asians (CT vs CC: OR =1.35, 95% CI =1.12-1.62; TT vs CC: OR =1.99, 95% CI =1.52-2.60; TT + CT vs CC: OR =1.41, 95% CI =1.16-1.71; and TT vs CC + CT: OR =1.74, 95% CI =1.41-2.14), especially in Chinese population (CT vs CC: OR =1.42, 95% CI =1.16-1.75; TT vs CC: OR =2.13, 95% CI =1.58-2.86; TT + CT vs CC: OR =1.50, 95% CI =1.21-1.87; and TT vs CC + CT: OR =1.80, 95% CI =1.43-2.26). In stratified analyses by cancer types, there was evidence for an association between this polymorphism and nasopharyngeal cancer and breast cancer, respectively.
  
  
  CONCLUSIONS
  The results of this meta-analysis suggest that the CD44 gene rs13347 C>T polymorphism is associated with elevated risk of human cancer in Asians, especially in Chinese population. Further well-designed studies on a larger population covering other ethnicities should be carried out to validate our results.
authors.affiliation: Department of Medical Oncology, Zhejiang Hospital, Hangzhou, Zhejiang Province, People's Republic of China.
authors.forename: Jinan
authors.initials: J
authors.lastname: Shi
authors.affiliation: Department of Breast Surgery, Zhejiang Provincial Traditional Chinese Medical Hospital, Hangzhou, Zhejiang Province, People's Republic of China.
authors.forename: Yin
authors.initials: Y
authors.lastname: Duan
authors.affiliation: Department of Breast Surgery, Zhejiang Provincial Traditional Chinese Medical Hospital, Hangzhou, Zhejiang Province, People's Republic of China.
authors.forename: Lei
authors.initials: L
authors.lastname: Pan
authors.affiliation: Department of Respiratory Medicine, Zhejiang Hospital, Hangzhou, Zhejiang Province, People's Republic of China.
authors.forename: Xiaoxi
authors.initials: X
authors.lastname: Zhou
keywords: CD44; cancer; meta-analysis; polymorphism