GPC3 and yolk sac tumor: IL21-armed CAR-T has been used in a clinical trial targeting several solid tumors expressing GPC3 antigen, including Liver Cancer, Rhabdomyosacoma, Malignant Rhabdoid Tumor, Liposarcoma, Wilms Tumor, and Yolk Sac Tumor (NCT04715191), but not ESCC.