In the most simplistic view, adult cancers occur because “immature cells are exposed to mutagens, accumulate mutations, and across life ultimately transform into cancer cells,” Franck Bourdeaut told his audience at the 2026 Annual Congress of the European Hematology Association (EHA 2026). “On the contrary, in pediatric cancers, it is assumed that very few mutations are responsible for a maturation block, make these cells derail from their normal differentiation trajectory and ultimately result in an early onset typical pediatric cancer.”