SUMO2 and disease arising from reactivation of latent virus: Cambogin, a bioactive natural product isolated from the Garcinia genus (a traditional herbal medicine used for cancer treatment), was obtained from the reporter system screening to efficiently inhibit the association of SUMO2 with LANASIM, in turn reducing the viral episome DNA copy number for establishment and maintenance of KSHV latent infection at a low concentration (nM).