The aims of the CARTES project were to evaluate anti-GD2 CAR T cells in ES preclinical models and develop CRISPR/Cas9-optimized anti-GD2 CAR T cells to ultimately potentiate CAR T cellbased therapy for the treatment of GD2-positive ES. Anti-GD2 CAR T cells produced tumor regression in a subcutaneous model of ES. Migration and infiltration of anti-GD2 CAR T cells into lung and liver metastatic nodules of ES were also confirmed, but without a significant control over tumor growth. A fine-tuning of the treatment schedule together with CRISPR/Cas9-based editing of anti-GD2 CAR T cells are currently challenged to improve the outcome in the metastatic model of ES. The training on gene-editing of T cells by CRISPR/Cas9 performed at UPenn will guide the development of CRISPR/Cas9-optimized anti-GD2 CAR T cells.