These efforts include: (i) targeting critical functional dependencies in tumors such as HER2 in breast cancer and BCR-ABL in CML (48–51); (ii) targeting TAAs such as CD19 in NHL and BCMA in multiple myeloma (52, 53); (iii) targeting tumor-specific antigens such as HPV E7 and other neoantigens in solid tumors (54–58); (iv) protease-cleavable masked cytotoxic proteins designed to activate selectively in solid tumors (59); and (v) logic-gated cell therapies that respond to antigen profiles rather than single antigens (60–63). This evidence concerns the gene CD19 and breast cancer.