555 Among them, Firmicutes and its metabolites may promote KS tumorigenesis by inducing an inflammatory response and reactivating KSHV.555 Another study has shown that Staphylococcus aureus in the oral cavity can promote KSHV lytic reactivation by upregulating ROS and inhibiting the cyclinD1-Dicer-viral microRNA axis, leading to KS tumorigenesis.556 These studies explain why HIV/KSHV-infected individuals who suffer from opportunistic bacterial infections and metabolic complications are prone to developing KS (Fig. 8h).557. This evidence concerns the gene CCND1 and Kaposi's sarcoma.