Pancreatic cancer continues to be a major unsolved health problem in the world. The prognosis of pancreatic cancer is extremely poor with a median survival of 3-4 months and the 5-year survival being 1-4%. This poor prognosis is primarily because of a lack of effective therapies, and thus development of new treatment modalities is needed. One of these treatments could involve specific immunotherapy, for which elucidation off the molecular basis of T cell-mediated recognition of cancer cells is required. We report here six different genes and 19 immunogenic epitopes from pancreatic adenocarcinoma cells and T-cell receptor beta usage of HLA-A2-restricted CTL clones reacting to some of these epitopes. Sixteen of 19 epitopes were found to possess the ability to induce HLA-A2-restricted CTL activity in the peripheral blood lymphocytes of patients with pancreatic and also colon adenocarcinomas. These results should provide a scientific basis for the development of specific immunotherapy for pancreatic and colon cancer patients.