CD4 and cancer: Seven steps of the cancer-immunity cycle were proposed to be necessary for the success in cancer immunotherapy: (1) cancer antigen presentation, (2) priming and (3) activation of T cells, (4) trafficking of T cells to tumors, (5) infiltration of T cells into tumor, (6) recognition of cancer cells by T cells, and (7) killing of cancer cells.8 WT1 peptide vaccine therapy induced WT1-specific CD4+ and CD8+ T cells in peripheral blood and infiltrated them into glioblastoma.