Importantly, however, this signature stemmed from only a minor percentage of lytic cells, which confounds the bulk sequencing data, since induction of the early viral lytic gene K-bZIP was seen in only <1% of the BC-3 culture by immunofluorescence analysis (Fig. S10D) and was not detected by bulk Western blotting upon IRF4 or vIRF3 KD in either BC-3 or BC-1 cells (Fig. S10E). This evidence concerns the gene IRF4 and breast cancer.