CD28 and breast cancer: Both NKp30CD28 CAR TCRKO and NKp30-CD137 CAR TCRKO, as well as NKp30-CD28 CAR TCR+ and NKp30-CD137 TCR+ T cells from different BCs (n = 4), here shown for the BC 1-92417103 (BC1) and BC 2-00645405 (BC2), were co-cultivated with irradiated HL60 targets at a 1:2 E/T ratio and T cell numbers determined after 5, 10, 17, 24, 30 and 45 days (d) of co-cultivation (Figure 3B).