B. fragilis contains the virulence gene B. fragilis toxin (BFT), which encodes the virulence protein BFT, interacting with the membrane receptors of IECs and immune cells via the STAT3 and NF-κB pathways, causing the expression of IL-17 downstream, promoting the expression of inflammatory factors and thus influencing the development of CRC (Chung et al., 2018). The gene discussed is PITX1; the disease is colorectal carcinoma.