The aim of this work is the investigation of the level of expression of the vascular endothelial growth factor (VEGF) and metalloproteases (such as Cox-2) in the colon rectal cancer. The final goal is the correlation with liver metastases. Molecular biology approaches will be adopted: in particular: RT-PCR, quantitative real time PCR with fluorescent probes, immunolocalizations and Western blotting This is a proposal of research. The work is under development and results and conclusions cannot be at the moment anticipated. However, in recent publication we found human polyomavirus DNA sequences in colorectal tumors.