Among these, we selected WT135 as an epitope with the most potent IFN-γ-producing capability of CD4+ T cells that strengthen the CTL-induced WT1-specific lysis of RMAS cells pulsed with WT135–52 peptide, suggesting its great potential of inducing CD4+ T cell help that provides critical cellular and molecular mechanisms in CTL responses in cancer immunotherapy [12]. Here, CD4 is linked to cancer.