WT1 and acute myeloid leukemia: Compared to the lack of reports showing clonality of TAA-specific CTLs in the PB of patients with solid tumors, as mentioned above, several investigations, including ours, have reported clonality of WT1-specific CTLs in the PB or bone marrow (BM) of patients with acute myeloid leukemia (AML), in which PB and BM are the areas where abundant leukemic cells exist, that is, tumor sites [18–20].