Vaccination of Qβ-MUC1-Tf 17 significantly protected MUC1.Tg mice from formation of metastatic-like tumor foci in the lungs. MUC1.Tg mice were immunized with Qβ-MUC1-Tf 17, Qβ, or PBS, respectively, on days 0, 14, and 28 with MPLA as the adjuvant. On day 35, the immunized mice were challenged with 1 × 105 B16-MUC1 cells via tail vein injection, followed by a fourth immunization. On day 45, the mice were given the last immunization. Twenty-one days after tumor inoculation, the mice were sacrificed and the number of tumor foci in the lungs were counted. Each symbol represents one mouse (n = 8–10 mice for each group); **p < 0.01. The p values are determined through two-way ANOVA with Bonferroni post-test using GraphPad Prism.