Rupp et al. demonstrated, using CD19+ PD-L1+ K562 cells, that PD-1 disrupted CAR T cells significantly enhanced anti-tumor efficacy in vitro and in vivo (tumor clearance rate of 17% for conventional anti-CD19 CAR T cells increased to 100% in animals receiving PD-1 edited CAR T cells at 28 days post tumor implant) [58,59]. The gene discussed is CD19; the disease is neoplasm.