This work was supported by the EMBRACE and CARCINOGENOMICS projects that are funded by the European Commission within its 6th Framework Programme under the thematic area ‘Life Sciences, Genomics and Biotechnology for Health’ (LSHG-CT-2004-512092 and LSHB-CT-2006-037712); 7th Framework Programme project APO-SYS (HEALTH-F4-2007-200767); German Federal Ministry of Education and Research within the NGFN-2 program (SMP-Protein, FKZ01GR0472); Max Planck Society within its International Research School program (IMPRS-CBSC). Funding for open access charge: European Commission.