Yu et al. [491] further showed that increased L1 expression in human fibrosarcoma cells and in testes and MEFs of Mov10l KO mice is marked by induction of IFN-β and IFN-stimulated genes (although, not unexpectedly, elevated IFN levels also inhibit L1 cell culture retrotransposition, perhaps by inducing restriction factors [250, 491]). The gene discussed is IFNA1; the disease is fibrosarcoma.