Enterotoxigenic Bacteroides fragilis (ETBF) can raise levels of chemokine L20 and prostaglandin E2 in intestinal epidermal cells; prostaglandin E2 plays a vital role in proliferation and enhances the secretion of IL-17 and related factors secreted by Th17 cells, leading to the development of inflammation-related CRC (110). The gene discussed is IL17A; the disease is colorectal carcinoma.