The group of Translational Research in Child and Adolescent Cancer, led by Dr. Josep Sanchez de Toledo and Dr. Soledad Gallego in the Vall d'Hebron Research Institute (VHIR), has identified a microRNA that prevents the growth of cells resistant to chemotherapy in neuroblastoma. The finding, published in http://www.impactjournals.com/oncotarget/index.php?journal=oncotarget&page=article&op=view&path[]=7005&pubmed-linkout=1" Oncotarget lays the foundation for the development of new therapies based on microRNAs for the treatment of childhood cancer.Neuroblastoma is a tumor of the sympathetic nervous system that occurs mainly in children aged 0 to 4 years. With a prevalence of 10.5 cases per million children in Europe and the United States, survival is excellent in low-risk patients, but is below 50% among high-risk patients, mainly due to resistance to current treatments.The laboratory of neural tumours, under the direction of Dr. Miguel Segura, develops the so-called 'epigenetic therapies', i.e., those based on altering the expression of genes without causing changes in the DNA sequence, and therefore safer, with fewer side effects. In this regard, microRNAs are seen as an alternative therapy because of its ability to regulate multiple genes and signalling pathways, minimizing the occurrence of resistance to therapy mechanisms.In this study, researchers analysed in human samples of neuroblastoma the expression levels of those genes associated with therapy resistance, and selected those that were highly expressed in the most advanced, and capable of being regulated by microRNAs, tumours. According to the study's lead author, Dr. Aroa Soriano, this strategy identified the microRNA-497 as a suppressor of tumour growth in cell and animal models. "We have seen that MiR-497 may be a new therapeutic tool for neuroblastoma, because of its ability to regulate multiple genes that are related to the cell cycle, survival and vascular permeability," explains the researcher.The research was funded by the Marie Curie program of the European Community, the Spanish Association Against Cancer and the Health Institute Carlos III. The group is currently working in a multidisciplinary way with experts in nanoparticles (Grupo Nanomol-ICMAB-CSIC and CIBBIM-Nanomedicina at VHIR) to administer the treatment directly into the tumour and thus increase the concentration and effectiveness of microRNAs.