In this thesis mass spectrometry based protein profiling was applied as a new biomarker screening modality and it was evaluated whether or not this could be translated into early detection... Show more In this thesis mass spectrometry based protein profiling was applied as a new biomarker screening modality and it was evaluated whether or not this could be translated into early detection of breast cancer and pancreatic cancer. The status of breast cancer screening by proteomic profiling is discussed. Which steps have already been made? What is essential to implement this techniques in a clinical setting? Furthermore, the new protein profiling screening methods for pancreatic cancers are evaluated. Future studies will be suggested that are needed to translate this promising biomarker into a clinical application. Show less