The objectives of this study were to assess the toxicity and immunological response induced by the intra-dermal (i.d.) administration of MUC1-peptide-pulsed dendritic cells (DCs) in advanced pancreatic cancer patients. Patients with recurrent lesions or metastasis after surgery, and immunohistochemistry positive for MUC1 were treated in cohorts that received 3-6 × 10(6) DCs i.d. for three or four vaccines. Each vaccine was composed of autologus DCs pulsed with MUC1-peptide. Peripheral blood mononuclear cells (PBMCs) that harvested 2 weeks after the second immunization were compared with PBMCs obtained before treatment for immunological response. Serial ELISPOT assays of PBMCs for antitumor reactivity were performed. Three patients received all four vaccines, and four patients received three vaccines. These patients were evaluable for toxicity and immunological monitoring. There were no grade 3 or 4 toxicities associated with the vaccines or major evidence of autoimmunity. Interferon-γ and granzyme B ELISPOT assay reactivity increased significantly in 2 of 7 patients (P < 0.05). The administration of MUC1-peptide-pulsed DCs is non-toxic and capable of inducing immunological response to tumor antigen MUC1 in advanced pancreatic cancer patients. Additional studies are necessary to improve tumor rejection responses.