Therapeutic immunization with the Mage-a1-Hsp70 fusion protein confers protection against the progression of established tumors. Mice were challenged with 1 × 105 B16-Mage-a1 cells. At 3 and 10 days post-tumor cell inoculation, mice were immunized with purified GST, Hsp70, Mage-a1, Mage-a1-Hsp70 fusion protein or a combination of Mage-a1 + Hsp70. A. The tumor free status of mice was recorded as the percentage of mice remaining tumor free after tumor challenge. B. Tumor growth was recorded as the mean tumor volume (in mm3). Error bars depict the SE, n = 8 mice/group. Statistical analysis by two-way ANOVA revealed that vaccination with Mage-a1-Hsp70 significantly delayed tumor growth in the B16-Mage-a1 tumor model compared to vaccination with Mage-a1 or Mage-a1 + Hsp70 from days 31 to 37 (* p < 0.05).