TLR4 and lung cancer: The exact role of TLRs in lung cancer promotion is not well established, therefore we sought to study the role of TLRs by crossing CC-LR mice with TLR2, TLR4, and TLR9 null mice separately to generate K-ras mutant mice lacking TLR2, TLR4, and TLR9, respectively (CC-LR/TLR2KO, CC-LR/TLR4KO, CC-LR/TLR9KO).