Godschalk, Roger W L3; Ersson, Clara3; Stępnik, Maciej3; Ferlińska, Magdalena3; Palus, Jadwiga3; Teixeira, João Paulo3; Costa, Solange3; Jones, George D D3; Higgins, Jennifer A3; Kain, Johanna3; Möller, Lennart3; Forchhammer, Lykke4; Loft, Steffen5; Lorenzo, Yolanda3; Collins, Andrew R3; van Schooten, Frederik-Jan3; Laffon, Blanca3; Valdiglesias, Vanessa3; Cooke, Marcus3; Mistry, Vilas3; Karbaschi, Mahsa3; Phillips, David H3; Sozeri, Osman3; Routledge, Michael N3; Nelson-Smith, Kirsty3; Riso, Patrizia3; Porrini, Marisa3; López de Cerain, Adela3; Azqueta, Amaya3; Matullo, Giuseppe3; Allione, Alessandra3; Møller, Peter4
1 Section of Occupational and Environmental Health, Department of Public Health, Faculty of Health and Medical Sciences, Københavns Universitet2 Department of Public Health, Department of Public Health, Faculty of Health and Medical Sciences, Københavns Universitet3 unknown4 Section of Occupational and Environmental Health, Department of Public Health, Faculty of Health and Medical Sciences, Københavns Universitet5 Department of Public Health, Department of Public Health, Faculty of Health and Medical Sciences, Københavns Universitet
This study investigated the levels of DNA strand breaks and formamidopyrimidine DNA glycosylase (FPG) sensitive sites, as assessed by the comet assay, in peripheral blood mononuclear cells (PBMC) from healthy women from five different countries in Europe. The laboratory in each country (referred to as 'centre') collected and cryopreserved PBMC samples from three donors, using a standardised cell isolation protocol. The samples were analysed in 13 different laboratories for DNA damage, which is measured by the comet assay. The study aim was to assess variation in DNA damage in PBMC samples that were collected in the same way and processed using the same blood isolation procedure. The inter-laboratory variation was the prominent contributor to the overall variation. The inter-laboratory coefficient of variation decreased for both DNA strand breaks (from 68 to 26%) and FPG sensitive sites (from 57 to 12%) by standardisation of the primary comet assay endpoint with calibration curve samples. The level of DNA strand breaks in the samples from two of the centres (0.56-0.61 lesions/10(6) bp) was significantly higher compared with the other three centres (0.41-0.45 lesions/10(6) bp). In contrast, there was no difference between the levels of FPG sensitive sites in PBMC samples from healthy donors in the different centres (0.41-0.52 lesion/10(6) bp).