Poxviruses are large DNA viruses that can be engineered to encode tumor-associated antigens such as PSA, HER-2, CEA and MUC-1, as well as immune-stimulatory cassettes, such as the triad of costimulatory molecules (TRICOM) encoding B7.1, ICAM-1 and LFA-3 [1–4]. The gene discussed is MUC1; the disease is neoplasm.