Meanwhile, studies have demonstrated in mouse models that MTB infection can stimulate the expression of EREG in a toll-like receptor 2 (TLR2) -dependent manner, and EREG binds to EGFR in membrane or soluble form to stimulate downstream signal transduction, thereby inducing activation and mutation of k-ras gene, leading to the occurrence of lung cancer (67, 68) (Figure 4). This evidence concerns the gene TLR2 and lung cancer.