SMO and cancer: The fundamental role of these VirFs could be to induce DNA damage response and subsequently activate the immune system, which results in pro-inflammatory outcomes and forms a microenvironment conducive to cancer.146 Microbial activities can also elicit the generation of reactive oxygen species (ROS), hydrogen sulphide, and superoxide dismutase.147–149 ETBF toxin increases the expression of spermine oxidase (SMO) in HT29/c1 and T84 colonic epithelial cells, triggering the SMO-dependent production of ROS and activation of γ-H2A, which causes DNA damage.56