The treatment is being evaluated for its effect on tumor growth. It consists of the placement (implantation) of small beads that contain mouse renal adenocarcinoma cells (RENCA macrobeads). The cells in the macrobeads produce substances that have been shown to slow or stop the growth of tumors in experimental animals and veterinary patients. It has been tested in 31 human subjects with different types of cancers in a Phase I safety trial. Phase II studies in patients with colorectal, pancreatic or prostate cancers are in progress