MMTV-like is a retrovirus and has the potential to upregulate IFN signaling and APOBEC-mediated mutagenesis in BC; and in this way it can increase genomic instability and tumor evolution [57] while promoting cancer cell apoptosis and immunological surveillance through recognition of viral antigens and APOBEC-generated neoepitopes by host immune system [55,58]. Here, IFNA1 is linked to breast cancer.