Systemic BC-PRV recognition as measured by whole blood mx1 transcription—a marker for interferon pathway activation—became elevated (4–8-fold) in both BC and NB-SJR salmon, although this activation was considerably more prolonged in BC salmon (observed 6–14 wpc) relative to NB-SJR salmon (observed only at 10 wpc; Figure 2B). This evidence concerns the gene MX1 and breast cancer.