The main objective of this project is to establish a Data Space for rare cancers (RC) that will make possible the re-use of existing multisource health data (cancer registry data, national registries, data from biobanks etc.) across European healthcare systems leveraging emerging interoperability technologies and AI approaches. The realized "Rare Cancer Data Ecosystem" is expected to improve the quality and the organization of RC patients care, and to increase knowledge on rare cancers advancing health research, so that all patients have equal access to high quality specialist care. The project approach will be experienced in the framework of the European reference network for rare adult solid cancers (EURACAN).