NFKB1 and renal cell carcinoma: In order to further clarify the role of NF-κB activation in the anti-tumor activity of sorafenib in RCC, Bay 11–7082 (inhibitor of NF-κB, which decreases NF-κB by inhibiting TNF-α-induced phosphorylation of IκB-α) was used for combination with sorafenib in Ketr-3 cells.