To validate the tumour-suppressive role of MRE11 in this breast cancer model, we injected an independent group of Rosa26LSL-Myc/LSL-cas9;Trp53fl/fl mice intraductally with lentivirus expressing Cre-sgControl (n = 22 glands) or Cre-sgMre11 (n = 40 glands). Here, MRE11 is linked to neoplasm.