This is a Phase I safety study of a gene transfer drug for colorectal cancer that has spread to the liver. The main purpose of this study is to determine if it is safe to give this new intervention to persons with cancer, but we will also look for indications that the drug is effective. Although the findings in animals that have cancer are encouraging, this is the first time humans will receive this experimental gene transfer drug. A gene called cyclin G1 has been shown to play a very important part in cancer growth. In animal experiments, a genetically modified virus (or vector)carrying a modified cyclin G1 gene caused the cancerous tumors to grow much slower or even die. In this safety study, the drug will be injected through the liver artery to get it near the cancer that has spread to the liver. The way the gene gets into the cancer cells is by using a targeted vector that concentrates in the area of the cancer to improve the delivery of the killing gene into cancer cells. The vector we are using is a virus that has been changed so that the infectious genes have been removed and instead carries the modified cyclin G1 gene.