CD28 and prostate cancer: To test whetherCAR-mediated cytotoxicity is enhanced upon shp2-knock out,we used our previously published second-generation CAR(scFv(J591)-CD8hinge-CD28TM-CD28-CD3z) (Kulemzinet al., 2019) that is specific for PSMA, a common surfacemarker of prostate cancer cells (Chang, 2004; Gorchakovet al., 2019).