• Evidence of gene gene interactions in lung carcinogenesis in a large pooled analysis.

      Vineis, Paolo; Anttila, Sisko; Benhamou, Simone; Spinola, Monica; Hirvonen, Ari; Kiyohara, Chikako; Garte, Seymour J.; Puntoni, Riccardo; Rannug, Agneta; Strange, Richard C.; et al. (2007-09)
      To test the hypothesis of interaction among genetic variants in increasing the individual risk of cancer, we have studied the cumulative effect on lung cancer risk of variants in three metabolic genes, CYP1A1, GSTM1 and GSTT1, which are involved in the metabolism of the tobacco smoke constituents and environmental contaminants, polycyclic aromatic hydrocarbons and of other lung carcinogens. We have selected from the Genetic Susceptibility to Environmental Carcinogens pooled analysis all the studies on lung cancer conducted after 1991 in which all variants were available. The data set includes 611 cases and 870 controls. We found a cumulative effect of the combination of the a priori 'at-risk' alleles for these genes (P for trend 0.004). The risk of lung cancer was increased with the combination of CYP1A1*2B or CYP1A1*4 alleles and the double deletion of both GSTM1 and GSTT1 up to an odds ratio (OR) of 8.25 (95% confidence interval 2.29-29.77) for the combination including CYP1A1*4; among never smokers, the latter combination was associated with an OR of 16.19 (1.90-137). Estimates did not change after adjustment by the number of cigarettes smoked and duration of smoking were consistent across ethnicities and were approximately the same for adenocarcinomas and squamous cell carcinomas. These observations from a large pooled analysis strongly suggest the existence of gene-gene interactions in lung carcinogenesis. People with rare combinations of common gene variants have a high risk of cancer and can be assimilated to subjects with highly penetrant mutations.
    • Indoor particles affect vascular function in the aged: an air filtration-based intervention study.

      Brauner, Elvira Vaclavik; Forchhammer, Lykke; Moller, Peter; Barregard, Lars; Gunnarsen, Lars; Afshari, Alireza; Wahlin, Peter; Glasius, Marianne; Dragsted, Lars Ove; Basu, Samar; et al. (2008-02-15)
      RATIONALE: Exposure to particulate matter is associated with risk of cardiovascular events, possibly through endothelial dysfunction, and indoor air may be most important. OBJECTIVES: We investigated effects of controlled exposure to indoor air particles on microvascular function (MVF) as the primary endpoint and biomarkers of inflammation and oxidative stress as secondary endpoints in a healthy elderly population. METHODS: A total of 21 nonsmoking couples participated in a randomized, double-blind, crossover study with two consecutive 48-hour exposures to either particle-filtered or nonfiltered air (2,533-4,058 and 7,718-12,988 particles/cm(3), respectively) in their homes. MEASUREMENTS AND MAIN RESULTS: MVF was assessed noninvasively by measuring digital peripheral artery tone after arm ischemia. Secondary endpoints included hemoglobin, red blood cells, platelet count, coagulation factors, P-selectin, plasma amyloid A, C-reactive protein, fibrinogen, IL-6, tumor necrosis factor-alpha, protein oxidation measured as 2-aminoadipic semialdehyde in plasma, urinary 8-iso-prostaglandin F(2alpha), and blood pressure. Indoor air filtration significantly improved MVF by 8.1% (95% confidence interval, 0.4-16.3%), and the particulate matter (diameter < 2.5 mum) mass of the indoor particles was more important than the total number concentration (10-700 nm) for these effects. MVF was significantly associated with personal exposure to iron, potassium, copper, zinc, arsenic, and lead in the fine fraction. After Bonferroni correction, none of the secondary biomarkers changed significantly. CONCLUSIONS: Reduction of particle exposure by filtration of recirculated indoor air for only 48 hours improved MVF in healthy elderly citizens, suggesting that this may be a feasible way of reducing the risk of cardiovascular disease.