In recent years, monoclonal antibodies have become one of the tools with the greatest potential to combat the appearance of tumours and the generation of metastases. But transforming them into effective drugs is not easy anywhere in the world. The use of organoids (microscopic organs) could speed up the development process. This is precisely what researchers at Barcelona Institute for Research in Biomedicine (IRB), under the direction of Eduard Batlle, and the Dutch company Merus NV have verified. After eight years' research, they have succeeded in producing an antibody that acts specifically on cancer stem cells and limits tumour growth and the formation of metastases. The study, which is based on the generation of an extensive biobank of organoids, was published on Monday in the journal Nature Cancer.