Paris Kids Cancer (PKC) is organizing its first international symposium, a major scientific event in pediatric oncology, on June 5 and 6, 2025 in Paris. This exceptional event will focus on the study of the development of the immune system during embryogenesis and childhood, its dysregulation and concrete applications for pediatric cancer research. PKC, a center of excellence in pediatric oncology in the Paris region accredited by the Institut National du Cancer and co-directed by AP-HP, Gustave Roussy and Institut Curie, will bring together international experts and leading researchers to advance knowledge in this crucial field.