The FRP5 antibody-based HER2-specific CAR molecule containing a CD28 co-stimulatory endo-domain (Fig. 1e) was detected in 72.9% of the patient’s T cells (Fig. 1f; gating strategy shown in Supplementary Fig. 2) and induced specific lysis of the HER2-positive sarcoma cells LM7 but not of the HER2-negative cell line K562 (Supplementary Fig. 1b)5. This evidence concerns the gene CD28 and sarcoma.