1 Institute of Physiological Chemistry and Pathobiochemistry, University of Münster, Waldeyerstr. 15, 48149 Münster, Germany. johannes.eble@uni-muenster.de.
2 Department of Biomedicine and Centre for Cancer Biomarkers, University of Bergen, Jonas Lies vei 91, NO-5009 Bergen, Norway. donald.gullberg@uib.no.