Cytokines secreted by tumor and tumor-associated cells within TME, such as transforming growth factor-β (TGF-β), IL-6, IL-10, prostaglandin E2 (PGE2), and so on can suppress NK cell activity (Konjevi ́c et al., 2019; Stojanovic et al., 2013). This evidence concerns the gene IL6 and neoplasm.