The PDX line WU-BC3 was generated by engrafting breast tumor cells from a patient with metastatic TNBC into the humanized mammary fat pads (MFPs) of NOD/SCID mice mice.26,27 We engineered these tumor cells to stably express Click Beetle Red Luciferase (CBR-Luc), mCherry, and an shRNA specific for p53 (shA2) to create the PDX line BC3_A2 (formerly known as BC3-p53KD28) (Supplementary Fig. 1a). This evidence concerns the gene TP53 and breast neoplasm.