TNF and neoplasm: For instance, colicin E3 (ColE3) and HlyE (also known as ClyA) have both shown increased tumor-killing ability when expressed in S. typhimurium [52, 53]. Salmonella expressing TNF-alpha family cytotoxic agents such as TNF-alpha, FAS ligand (FASL), and TNF-related apoptosis-inducing ligand (TRAIL) can enhance cytotoxic effects against many kinds of tumors [54–56].