IL6 and neoplasm: NK cells directly induce anti-tumor activity by secreting pro-inflammatory cytokines and chemokines such as IFN-γ, tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), granulocyte–macrophage colony-stimulating factor (GM-CSF), and chemokine (C–C motif) ligand 5 (CCL5) and also promote innate and adaptive responses [61].