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. The gene discussed is GPC3; the disease is liver cancer.