In solid cancers, clinical data are inadequate for meaningful comparisons of CAR designs, but animal studies suggest that CARCD28ζ T cells targeting GPC-2, mesothelin, IL13Rα2, B7-H3, and HER2 produce more rapid control of neuroblastoma, ovarian cancer, glioma, osteosarcoma/glioma, and osteosarcoma, respectively (19–24). This evidence concerns the gene MSLN and osteosarcoma.