In this dissertation the prognostic and/or predictive valuesofpretherapeutic levels (PTL)for the overall survival (OS) and progressive free survival (PFS)in patients treated for metastatic colorectal cancer with bevacizumab (BEV) and/ or cetuximab were investigated. PTLof alkaline phophatase (AP), carbohydrate antigen 19 9 (CA 19 9), carcinoembryonic antigen and lactatedehydrogenase, as well as the administrationof certain monoclonal antibodies (mAb) altogether or as start therapy were examined. In a multivariate analysis PTL of AP and CA 19-9 were found to be prognostic for OS, whereupon a low PTL militates for a better OS. Forthe PFS, CA19-9 and the first givenmAbproved to be prognostic. A low PTL leads to a better PFS as does the administration of BEV as first mAb. None of the investigated variables were predictive.