Moreover, several TME-associated cells, such as tumor-associated macrophages (TAMs), myeloid-derived suppressor cells (MDSCs), and regulatory T-cells (Tregs) could dampen NK cell cytotoxic activities by direct contact and secretion of soluble factors TGF-β and prostaglandin E2 [45,60,71,72] (Figure 1). This evidence concerns the gene TGFB1 and neoplasm.