It therefore becomes of paramount interest to extend these studies to a human system of widespread clinical relevance to explore the clinical potential of this new technology. The target antigen for these studies is carcinoembryonic antigen (CEA), which is prominently expressed on tumors of the stomach, colon and rectum, breast, pancreas and other sites. Patients receive a single dose of gene-modified autologous T cells on this dose-escalation trial. Doses are 10^9, 10^10 and 10^11 modified T cells. Patients are monitored for safety and response. Patients are on-study for one month after dosing.