IL15 and neoplasm: For instance, Yang et al. stated that the intratumoral administration of a circRNA mixture encoding four cytokines (including interleukin-15 (IL-15), interleukin-12 (IL-12), granulocyte–macrophage colony-stimulating factor (GM-CSF), and interferon-α2b (IFN-α2b)) can lead to the activation of T cells (CD4+ and CD8+ T cells) and promote the infiltration of immune cells, thus exerting a powerful anti-tumor effect [45].