FN1 and colorectal carcinoma: In a recent study, Fn has been identified as an important intratumoral bacterium and implicated in the development of various gastrointestinal tumors, including esophageal, gastric, and colon tumors.[1,5,6] Overwhelming evidence has demonstrated that Fn is the most critical microbial risk factor in colorectal cancer (CRC) initiation and progression.[1,7,8]