1 Department of Cell and Molecular Biology (CMB), Karolinska Institutet Stockholm, Sweden.
2 Department of Oncology, University of Oxford, Oxford, UK.
3 Institute of Cancer Biology and Center for Genotoxic Research, Danish Cancer Society, Copenhagen, Denmark.
4 Experimental Cell Research Karolinska Institutet, Department of Cell and Molecular Biology (CMB) Stockholm, Sweden. Electronic address: christer.hoog@ki.se.