In gut microbiota-related cancer, previous data have suggested that the free fatty acid receptor 2 (FFAR2) and SCFAs (propionate, butyrate, and acetate), as the most significant microbiota metabolites, act on G protein-coupled and are involved in pro-inflammatory cytokine generation, intestinal immune reactions, and reducing carcinogenesis [15,16]. Here, FFAR2 is linked to cancer.