To test whether activation, or lack thereof, of the IFN-β/IFNAR1/IRF7 pathway during chemotherapy might correlate with a better, or worse outcome, respectively, we determined IFN levels in the serum of 51 ER− breast cancer patients of the trial of principle (TOP) study [36] treated with neoadjuvant Epirubicin chemotherapy. This evidence concerns the gene IFNA1 and breast cancer.