The interplay described between the IGF-1R signaling system and JCV T-antigen in the process of DNA repair could be relevant, since nearly 90% of the human population is seropositive for JC virus, the JCV T-antigen transforms cells in vitro, the JCV T-antigen is tumorigenic in experimental animals, and the presence of the JC virus has been noted in an increasing number of biopsies of human cancer (32). Here, IGF1R is linked to cancer.