title: The contribution of molecular epidemiology to the identification of human carcinogens: current status and future perspectives.
abstract: BACKGROUND
  The use of biological-based markers of exposure, intermediate effect, outcome, and susceptibility has become standard practice in cancer epidemiology, which has contributed to identification of several carcinogenic agents. Nevertheless, with the exception of biological agents, this contribution, in terms of providing sufficiently strong evidence as required by the International Agency for Research on Cancer (IARC) monographs, has been modest.
  
  
  METHODS
  We discuss the overall contribution of molecular epidemiology to identification of carcinogens, with focus on IARC monographs.
  
  
  RESULTS
  For many carcinogens, valid biological markers of exposure and mechanisms of actions are not available. Molecular markers are usually assessed in single biological samples, which may not represent the actual exposure or biological events related to carcinogens. The contribution of molecular epidemiology to identification of carcinogens has mainly been limited to the carcinogens acting through a genotoxic mechanism, i.e. when carcinogens induce DNA damage. A number of factors, including certain hormones and overweight/obesity, may show carcinogenic effects through nongenotoxic pathways, for which mechanisms of carcinogenicity are not well identified and their biomarkers are sparse.
  
  
  CONCLUSIONS
  Longitudinal assessment of biomarkers may provide more informative data in molecular epidemiology studies. For many carcinogens and mechanistic pathways, in particular nongenotoxic carcinogenicity, valid biological markers still need to be identified.
authors.affiliation: The Tisch Cancer Institute and Institute for Translational Epidemiology, Mount Sinai School of Medicine, NY 10029, USA. paolo.boffetta@mssm.edu
authors.forename: P
authors.initials: P
authors.lastname: Boffetta
authors.forename: F
authors.initials: F
authors.lastname: Islami
mesh_terms: D014408:Biomarkers, Tumor; D015197:Carcinogenicity Tests; D002273:Carcinogens / Q000302:isolation & purification / Q000633:toxicity*; D004249:DNA Damage / Q000187:drug effects; D004781:Environmental Exposure; D006801:Humans; D017720:Molecular Epidemiology; D009369:Neoplasms / Q000139:chemically induced* / Q000453:epidemiology* / Q000473:pathology
chemical_list: D014408:Biomarkers, Tumor; D002273:Carcinogens