To explore if MYC regulates immune responses in mammary tumors in vivo, we used four genetically engineered mouse models (GEMM) of BRCA1-proficient and -deficient TBNC with or without engineered MYC overexpression: WapCre;Trp53F/F (WP), WapCre;Trp53F/F;Col1a1invCAG-Myc-IRES-Luc/+ (WP-Myc), WapCre;Brca1F/F;Trp53F/F (WB1P) and WapCre;Brca1F/F;Trp53F/F;Col1a1invCAG-Myc-IRES-Luc/+ (WB1P-Myc)20. Here, MYC is linked to breast cancer.