Thus, we speculated that Fn infection may facilitate CRC malignancy involving Mφ activation, either directly or indirectly, via activating specific signal pathways such as that of TLR4-dependent NF-κB. Now we have shown that PAMP extracted from Fn and Fn itself could be recognized by TLR4, which further activates its downstream signaling cascade in CRC (8, 21). This evidence concerns the gene FN1 and colorectal carcinoma.