To study the effects of influenza virus infection on the awakening of dormant breast DCCs already lodged in the lung, we used the well-established MMTV-ErbB2/Neu/Her2 (hereafter MMTV-Her2) mouse model of breast cancer metastatic dormancy, in which mice overexpress rat Neu (Erbb2, a paralogue of human HER2) in epithelial mammary gland cells13,14. Here, ERBB2 is linked to breast cancer.