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,

Molecular biomarkers to assess health risks due to environmental contaminants exposure

“…Many environmental pollutants have the ability to induce ROS production, such as particulate matter (PM), traffic-related contaminants, wood smoke and heavy metals, among others (25,32,33). Overall, there is strong evidence that there is an association between environmental air pollution and the urinary excretion of 8-oxodG or 8-oxoGua, biomarkers that are widely used to assess endogenous oxidative DNA damage (25).…”

“…Different enzymatic pathways are dedicated to maintenance of the correct balance between pro-oxidative and anti-oxidative status, but some exogenous stimuli may shift this equilibrium and induce a pro-oxidant condition that can damage cell integrity. As is well known, ROS are able to modify the DNA nucleobases and generate mutations when those are not repaired by the corresponding mechanisms (25). Although a wide number of oxidative modifications of DNA have been described, the oxidation of guanine generates 8-oxo-7,8-dihydroguanine (8-oxoGua) and its deoxynucleoside, 8-oxo-7,8-dihydro-2ˈ-deoxyguanosine (8-oxodG), which are the most commonly measured products of oxidative DNA damage (31).…”

“…Overall, there is strong evidence that there is an association between environmental air pollution and the urinary excretion of 8-oxodG or 8-oxoGua, biomarkers that are widely used to assess endogenous oxidative DNA damage (25).…”

“…Many environmental air pollutants (20), tobacco smoke (20)(21)(22) and PAHs from traffic exhaust (23,24) or from occupational exposure (21) have shown a positive correlation with DNA adduct formation in exposed populations. For further information, see reference (25).…”

“…The alteration of the normal arrangement of chromosomes by deletions, duplications or reorganizations of the genome that can be visualized microscopically is defined as a chromosomal aberration (CA) (25,43). Doublestranded breaks of DNA (DSB) are the main source for CAs and are naturally produced during DNA synthesis by the accumulation of single stranded breaks through excision DNA repair, oxidative DNA modifications, and other processes or by external stimuli, such as UV and ionizing radiation, mutagens, antibiotics or nucleases (43).…”