Objective: The objective of this project is to explore the usefulness of zebrafish (Danio Rerio) embryo models to determine tumor biology and treatment response in colon cancer. An overarching goal would be, before start of any oncological treatment in a patient, to have evaluated the response of oncological treatment in the zebrafish avatar and only treat with a combination of drugs known to have effect against the patient's own tumour. 2.3 Study design: This protocol describes a series of prospective studies in different cohorts of patients with colon cancer to investigate the applicability of zebrafish embryo models. The common denominator of the sub-studies is prospective collection of tumor tissue implanted in zebrafish embryos in order to evaluate if the model is robust enough for growing colon cancer tissue and evaluate growth pattern and response to chemotherapy. This study protocol is designed according to and in adherence with the SPIRIT guidelines. 2.4 Intervention: In all sub-studies the intervention is inoculation of tumor cells in zebrafish embryos followed by observation of tumor behavior and testing of treatments.