More than ten small-scale clinical trials have been performed using experimental vaccines predominantly based on the p210 BCR-ABL fusion protein[21], and other attractive targets include the Wilms' tumor 1 (WT1) antigen and the PR1 epitope from proteinase 3, a granule protein overexpressed in CML. This evidence concerns the gene ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive.