We have used antibody-based proteomics to construct a comprehensive, antibody-based protein atlas for expression and localization profiles in normal human tissues and different cancers. The Human Protein Atlas contains more than 2,8 million high-resolution images and is publicly available (www.proteinatlas.org). Our results suggest it should be possible to extend this analysis to the majority of all human proteins thus providing a valuable tool for medical and biological research, in particular for biomarker analysis in various patient cohorts.