We found that P4 treatment dose-dependently potentiated SeV-induced transcription of antiviral IFNB1, ISG56 and CXCL10 genes in mouse primary bone marrow-derived dendric cells (BMDCs) and human breast cancer T-47D cells (Fig. 3a), both expresses PGR (Fig. S3c).57 In similar experiments, P4 had no marked effects on IFN-γ-induced transcription of IRF1 gene in these cells (Fig. 3b). Here, IFIT1 is linked to breast cancer.