Indeed, leukemia targeted chimeric antigen receptors (CARs) such as CD19-CARs in B-cell acute lymphoblastic leukemia (B-ALL) or T cell receptors (TCRs) targeting Wilms Tumor 1 (WT1) or the minor histocompatibility antigen HA-1H in acute myeloid leukemia (AML) have been expressed in VSTs and infused to patients post-transplant (4–9). Here, WT1 is linked to leukemia.