In addition, the enterotoxigenic B. fragilis (ETBF), an anaerobic bacterium found in the human intestinal microbiota, produces an enterotoxin (B. fragilis toxin, BFT), which is highly associated with CRC [21], by activating β-catenin signaling as well as the secretion of interleukin (IL)-8 in colonic epithelial cells, leading to persistent cellular proliferation [22]. Here, CXCL8 is linked to colorectal carcinoma.