title: Telomerase reverse transcriptase locus polymorphisms and cancer risk: a field synopsis and meta-analysis.
abstract: BACKGROUND
  Several recent studies have provided evidence that polymorphisms in the telomerase reverse transcriptase (TERT) gene sequence are associated with cancer development, but a comprehensive synopsis is not available. We conducted a systematic review and meta-analysis of the available molecular epidemiology data regarding the association between TERT locus polymorphisms and predisposition to cancer.
  
  
  METHODS
  A systematic review of the English literature was conducted by searching PubMed, Embase, Cancerlit, Google Scholar, and ISI Web of Knowledge databases for studies on associations between TERT locus polymorphisms and cancer risk. Random-effects meta-analysis was performed to pool per-allele odds ratios for TERT locus polymorphisms and risk of cancer, and between-study heterogeneity and potential bias sources (eg, publication and chasing bias) were assessed. Because the TERT locus includes the cleft lip and palate transmembrane 1-like (CLPTM1L) gene, which is in linkage disequilibrium with TERT, CLPTM1L polymorphisms were also analyzed. Cumulative evidence for polymorphisms with statistically significant associations was graded as "strong," "moderate," and "weak" according to the Venice criteria. The joint population attributable risk was calculated for polymorphisms with strong evidence of association.
  
  
  RESULTS
  Eighty-five studies enrolling 490 901 subjects and reporting on 494 allelic contrasts were retrieved. Data were available on 67 TERT locus polymorphisms and 24 tumor types, for a total of 221 unique combinations of polymorphisms and cancer types. Upon meta-analysis, a statistically significant association with the risk of any cancer type was found for 22 polymorphisms. Strong, moderate, and weak cumulative evidence for association with at least one tumor type was demonstrated for 11, 9, and 14 polymorphisms, respectively. For lung cancer, which was the most studied tumor type, the estimated joint population attributable risk for three polymorphisms (TERT rs2736100, intergenic rs4635969, and CLPTM1L rs402710) was 41%. Strong evidence for lack of association was identified for five polymorphisms in three tumor types.
  
  
  CONCLUSIONS
  To our knowledge, this is the largest collection of data for associations between TERT locus polymorphisms and cancer risk. Our findings support the hypothesis that genetic variability in this genomic region can modulate cancer susceptibility in humans.
authors.affiliation: Department of Oncological and Surgical Sciences, Meta-analysis Unit, University of Padova, Padova, Italy. simone.mocellin@unipd.it
authors.forename: Simone
authors.initials: S
authors.lastname: Mocellin
authors.forename: Daunia
authors.initials: D
authors.lastname: Verdi
authors.forename: Karen A
authors.initials: KA
authors.lastname: Pooley
authors.forename: Maria T
authors.initials: MT
authors.lastname: Landi
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Egan
authors.forename: Duncan M
authors.initials: DM
authors.lastname: Baird
authors.forename: Jennifer
authors.initials: J
authors.lastname: Prescott
authors.forename: Immaculata
authors.initials: I
authors.lastname: De Vivo
authors.forename: Donato
authors.initials: D
authors.lastname: Nitti
mesh_terms: D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D015810:Linkage Disequilibrium; D008565:Membrane Proteins / Q000235:genetics*; D009363:Neoplasm Proteins / Q000235:genetics*; D009369:Neoplasms / Q000235:genetics*; D016017:Odds Ratio; D020641:Polymorphism, Single Nucleotide; D012307:Risk Factors; D019098:Telomerase / Q000235:genetics*
chemical_list: C422445:CLPTM1L protein, human; D008565:Membrane Proteins; D009363:Neoplasm Proteins; C509186:TERT protein, human; D019098:Telomerase