title: Biomarkers of ambient air pollution and lung cancer: a systematic review.
abstract: The association between ambient air pollution exposure and lung cancer risk has been investigated in prospective studies and the results are generally consistent, indicating that long-term exposure to air pollution may cause lung cancer. Despite the prospective nature and consistent findings of these studies, causality assessment can benefit from biomarker research. In the present systematic review, we assess the contribution of intermediate biomarkers in epidemiological studies, to ascertain whether their measurement reinforces causal reasoning. We have reviewed 524 papers which described the relationships between ambient air pollution and biological markers of dose and early response. The evidence for each marker was evaluated using assessment criteria which rate a group of studies from A (strong) to C (weak) on amount of evidence, replication of findings, and protection from bias. Biomarkers that scored A or B for all three criteria are included here. The markers that fulfilled the inclusion criteria are: 1-hydroxypyrene, DNA adducts, chromosomal aberrations, micronuclei, oxidative damage to nucleobases, and methylation changes. These biomarkers cover the whole spectrum of disease onset and progression from external exposure to tumour formation and some have also been suggested as risk predictors of future cancer, reinforcing causal reasoning. However, methodological issues such as confounding, publication bias and use of surrogate tissues instead of target tissues in studies on these markers are of concern. The identified biological markers have potential to shed light on the pathways of carcinogenesis, thus defining the association more clearly for public health interventions.
authors: Department of Epidemiology and Biostatistics, Imperial College London, London, UK. christiana.demetriou08@imperial.ac.uk
authors: Christiana A
authors: CA
authors: Demetriou
authors: Ole
authors: O
authors: Raaschou-Nielsen
authors: Steffen
authors: S
authors: Loft
authors: Peter
authors: P
authors: Møller
authors: Roel
authors: R
authors: Vermeulen
authors: Domenico
authors: D
authors: Palli
authors: Marc
authors: M
authors: Chadeau-Hyam
authors: Wei W
authors: WW
authors: Xun
authors: Paolo
authors: P
authors: Vineis
mesh_terms: D000397:Air Pollution / Q000009:adverse effects*; D015415:Biomarkers; D018736:DNA Adducts; D004781:Environmental Exposure / Q000009:adverse effects*; D006801:Humans; D008175:Lung Neoplasms / Q000209:etiology*; D008745:Methylation; D048629:Micronuclei, Chromosome-Defective; D018384:Oxidative Stress; D011721:Pyrenes
chemical_list: D015415:Biomarkers; D018736:DNA Adducts; D011721:Pyrenes; C033146:1-hydroxypyrene