At the molecular level, chemosensitive MCF-7 breast cancer cells resistant to TNF exhibited reduced expression of TNF receptor 1 (TNFR1) and TNFR1-associated death domain protein (TRAD), which blocked extrinsic apoptosis and increased the nuclear factor-kappa B (NF-κB) survival pathway. The gene discussed is NFKB1; the disease is breast cancer.