CD4 and neoplasm: The growth of the secondary tumor was inhibited (Fig. 6b–d), and the population of infiltrating CD4+ and CD8+ T cells in the secondary tumor was increased by 2.1- and 2.7-times, respectively (Fig. 6e), in the treated groups, suggesting that the systemic antitumor immune response induced by local treatment with iGel inhibited metastasis.