Ectopic expression of the NTF of tmTNF-α in MCF-7 leads to constitutive activation of NF-κB and resistance to sTNF-α-mediated cytotoxicity [21], suggesting a possible role of tmTNF-α-mediated reverse signaling in constitutive activation of NF-κB in tumor cells. This evidence concerns the gene NFKB1 and neoplasm.