Given the natural history of colorectal and breast cancer, early diagnosis appears to be the most appropriate tool to reduce disease-related mortality.[6;7] Currently, there is no early diagnostic... Show moreGiven the natural history of colorectal and breast cancer, early diagnosis appears to be the most appropriate tool to reduce disease-related mortality.[6;7] Currently, there is no early diagnostic test with high sensitivity, specificity and positive predictive value, which can be used as a routine screening tool. Therefore, there is a need for new biomarkers for both types of cancer that can improve early diagnosis, monitoring of disease progression and therapeutic response and detect disease recurrence. Proteomic expression profiles generated with mass spectrometry have been suggested as potential tools for the early diagnosis of cancer and other diseases. Because it is still in its infancy, many problems have to be overcome before clinical proteomics can be transferred form bench to bedside. Chapter 2 gives an insight in the different fields of translational research in colorectal cancer by our group. In chapter 3 reliability of human serum protein profiling using MALDI-TOF mass spectrometry is analysed. We present a pipeline for pre-processing, statistical data analysis and presentation of MALDI-TOF spectra. This novel analysis method was used to assess the effect of variable pre-analytical conditions on human serum protein profiles, and their effect on reproducibility. In line with the logistic conditions in a routine clinical setting, the effects of sample handling and storage, and also circadian rhythm factors on the serum protein profiles were analysed. In chapter 4 and 5 the feasibility of mass spectrometry based protein profiling for the discrimination of colorectal cancer patients from healthy individuals was assessed. In addition to standardizing technical factors and biological variations, we performed blinded tests and employed a randomised block design experimentation to minimize impact of potential confounding factors and to avoid bias. Especially, validation of our classifier, as a possible pitfall, was given much attention. Therefore, we performed a linear discriminant analysis with double cross-validation to separate cancer patients from healthy subjects. Chapter 6 reports on results from an identical designed protein profiling study for the detection of breast cancer. In chapter 7 a first validated study on the detection of breast cancer based on mass spectrometry generated protein profiles is described. In this study the same randomised blocked design and double cross validation is used, however the classifier was validated in an independent set of new patients and controls. Finally, the results and conclusions of all above mentioned studies and especially the current status of clinical proteomics in cancer are discussed in chapter 8. A Dutch summary of this thesis is written in chapter 9. Show less
In order to form a distant metastasis, a cancer cell has to migrate out of the primary tumor, intravasate into a blood or a lymphatic vessel, subsequently survive in the absence of cell-cell and... Show moreIn order to form a distant metastasis, a cancer cell has to migrate out of the primary tumor, intravasate into a blood or a lymphatic vessel, subsequently survive in the absence of cell-cell and cell-matrix interactions, extravasate the blood or lymphatic vessel, migrate through the target organ and finally proliferate to grow out into a full metastasis. During all of these processes, specific kinases are involved in the concerted activation of distinct signaling pathways. We hypothesised that the protein tyrosine kinase FAK plays a crucial role in one or multiple of the processes involved in the formation of metastases. Therefore, the overall aim of the studies described in this thesis was to investigate the role of the non-receptor protein tyrosine kinase FAK in the distinct processes involved in tumorigenesis and metastasis and to unravel the involved downstream signaling pathways. Moreover, the potential of a combined therapy of the inhibition of FAK and exposure to the cytostatic doxorubicin was tested, as well as dissection of the intracellular events downstream of FAK. Show less
