title: Association of p16 gene methylation with prostate cancer risk: a meta-analysis.
abstract: OBJECTIVE
  The tumor suppressor gene p16 is frequently silenced and inactivated by hypermethylation in human cancers, including prostate cancer. However, the association between the methylation status of p16 and prostate cancer risk remains ambiguous. This study aimed to assess the association of p16 methylation with prostate cancer risk by a comprehensive metaanalysis.
  
  
  METHODS
  Relevant studies were identified by searching PubMed, Embase and Web of Science databases before October 2014 with no restrictions. The strength of the association between p16 methylation and prostate cancer risk was assessed by combined odds ratio (OR) and 95 % confidence interval (CI). The between-study heterogeneity and the contributions of single studies to the final results were tested by chi-square-based Q test and sensitivity analyses, respectively. Publication bias was evaluated by funnel plots.
  
  
  RESULTS
  A total of 1,296 samples from 12 independent studies were enrolled in the present metaanalysis. Overall, a significant association was observed between p16 methylation and prostate cancer risk (OR=3.06; 95% CI:1.34- 6.98;p=0.008). Stratified analyses by ethnic groups further revealed that prostate cancer risk was increased for individuals carrying the methylated p16 compared with those with unmethylated p16 in Caucasian populations (OR=2.51;95% CI:1.01-6.26;p=0.047) and Asian populations (OR=9.50;95% CI:1.78-50.61;p=0.008).
  
  
  CONCLUSIONS
  This study identified a strong association of p16 methylation with prostate cancer risk and suggested that p16 methylation might be a potential biomarker for prostate cancer.
authors.affiliation: Department of Accident and Emergency, Zaozhuang Mining Group Central Hospital, Zaozhuang 277800, P.R. China.
authors.forename: Wen
authors.initials: W
authors.lastname: Feng
authors.forename: Zhi
authors.initials: Z
authors.lastname: Han
authors.forename: Ruixia
authors.initials: R
authors.lastname: Zhu
authors.forename: Peiyue
authors.initials: P
authors.lastname: Liu
authors.forename: Sihai
authors.initials: S
authors.lastname: Liu
mesh_terms: D019175:DNA Methylation; D019942:Genes, p16; D006801:Humans; D008297:Male; D011471:Prostatic Neoplasms / Q000209:etiology / Q000235:genetics*; D017594:Publication Bias; D012306:Risk