The induced ablation of IKKβ in AT-II lung epithelial cells significantly reduced the numbers and sizes of lung adenomas 6 mo after the first urethane injection (Fig 2A and B), indicating that IKKβ (unlike IKKα) acts as a promoter of NSCLC development in this in vivo urethane-based LC model. This evidence concerns the gene IKBKB and laryngotracheoesophageal cleft.