Strong CLDN6 expression was also detected in single samples of hepatoblastoma, Ewing sarcoma/other embryonal tumors, and osteosarcoma.In experimental models, CLDN6-CAR T cells led to antigen-specific killing of endogenously CLDN6-expressing AT/RT cell lines in vitro and exhibited potent and specific antitumor activity in mice bearing orthotopic CLDN6-expressing AT/RT xenograft tumors.<h4>Conclusions</h4>These results support CLDN6 as an oncofetal cell-surface antigen that may be suitable for CAR T-cell targeting in pediatric solid tumors, including those of the CNS. This evidence concerns the gene CLDN6 and Ewing sarcoma.