The breakthrough objective of NANOTHER is to develop & characterise a novel nanoparticle system that will be used as a therapeutic agent or diagnosis tool for breast cancer, colorectal cancer & bone metastasis. Theranostics, the development of nanoparticles with both functionalities, will also be carried out using the hyperthermic effect to kill tumour cells or to release the selected drug . The nanoparticles used in NANOTHER will be selected based on previous studies. Therefore, only polymeric micelles core-shell nanoparticles and magnetic nanoparticles will be included in the study. The nanoparticles will be functionalised by attaching targeting molecules, depending on the type of cancer to be treated or diagnosed. Labels for diagnosis will include fluorescent or contrast phase probes, which will later be imaged and analysed with the appropriate equipment optimised during the project. Therapeutic agents will be loaded on to the nanoparticle, including drugs like doxorubicin, and new marine pharmacological compounds already in clinical trials. One of the most innovative aspects of this proposal is the use of siRNA as the therapeutic agent. The use of magnetic nanoparticles as a theranostic mechanism is also an innovative aspect of the proposal, as these nanoparticles can be activated to kill tumour cells detected depending on a positive or negative diagnostic. The project has been structured in seven different sub-projects including aspects like toxicology, biocompatibility of the nanodevices, and also efficacy and biodistribution of the system. In vitro (cellular models) & in vivo assays (small animals; mice) will be used for the study of diagnosis & therapy. The latter will be kept to the minimum necessary to study the efficiency & biodistribution and always taking into account the three Rs & national / EU norms. The NANOTHER consortium includes 18 top-level partners from 8 EU countries as the critical mass required to achieve ambitious project objectives.