In order to improve and individualize cancer treatment, personalized treatment needs to be developed much further. Liver metastasizing colorectal cancer is treated with a combination of oncological and surgical interventions. The selection of chemotherapy is today mainly done according to best guess. Today only a small fraction of oncological treatment may be known to be effective in a person before treatment start, most often it is trial and error. A fast reliable system for looking at response to different treatments in each unique patient is much needed and would, if successful, completely change the way we give oncological treatment today. Patient's tumor tissue will be evaluated with use of zebrafish embryo avatars to evaluate tumour growth and response to different combinations of chemotherapy. If successful interventional studies are planned.