We study three human cancer diseases, colorectal cancer (CRC), testicular germ cell tumour (TGCT), and malignant peripheral nerve sheath tumour (MPNST), originating from different types of stem cells. All three diseases develop through morphologically def ined stages, and the stepwise molecular biology of these diseases are being studied. Common changes or disruptions of the same cellular pathways will provide new insights to tumourigenesis in general and have impact on the molecular understanding of embry ogenesis. The identified sets of molecular discriminators will be clinically validated in large patient cohorts. A molecular stratification of each cancer type both for complex datasets and for individual markers will be performed in order to predict pati ent treatment and disease outcome. We have access to the necessary human material ensuring the biological premises of the outlined project. The technological availability and know-how are presented in the application. Interaction with the dept. Pathology ensures the contribution from national reference pathologists and joint facilities for molecular pathology technologies. Our group has long term connections to relevant clinical milieus, and to explore diagnostic and clinical relevant questions. One of th e most challenging clinical questions and one of the main issues of the present project, is how to use the available new technology to identify CRC patients in need for aggressive treatment and those who are better off not receiving it. The letters of sup port from our two co-applicants confirms the close interaction with the Pathology dept. and clinic. Finally, national ethical demands are taken care of.