These data are surprising, considering previous reports showing that PARP9 and DTX3L overexpression increases ISG induction in response to IFN signaling in human fibrosarcoma cells (27) and that PARP9 silencing reduces IFNγ-induced STAT1 phosphorylation and ISG induction in macrophages (35). The gene discussed is IFNA1; the disease is fibrosarcoma.