Therefore, these pre-clinical results suggest that OCV-501 activates both direct and indirect antitumor (anti-leukemic) cellular immunity, including specific cytotoxic Th1 cells and WT1-peptide-specific CTL cells, however, it is necessary to confirm the cytolytic activity of OCV-501-specific Th1 cells against several AML-derived leukemic cell lines. This evidence concerns the gene WT1 and acute myeloid leukemia.