TP53BP1 and breast cancer: To address the possibility that mtp53 coordinated the MDM2–53BP1 PLA interaction, we carried out PLA analysis of MDM2-53BP1 within the MDA-MB-468 (mtp53 R273H) breast cancer cell line and an MDA-MB-468 derivative in which CRISPR-Cas9 was used to delete the mtp53 C-terminal domain that interacts with MDM2 (Fig. 3A) [36, 39].