ONTHETRRAC

Background & rationale: Neuroblastoma (NB) is the most devastating solid tumour in childhood. Extensive clinical/translational research has led to valuable prognostic classifiers for risk-adapted therapy, but intratumour genetic heterogeneity (ITH) limits the accuracy of classifiers generated from single biopsies of bulky tumours. Spatial/temporal ITH is a major obstacle to effective treatment and the true extent has only recently been hinted at by progress in sequencing technology. Highly sensitive, precise molecular diagnostic tools are needed to detect the relapse seeding clone and (sub)clonal mutations conferring therapy resistance. The entire spectrum of druggable gene mutations involved in resistance and relapse must be identified to make use of the increasing availability of drugs specifically targeting mutated genes. ONTHETRRAC joins expertise of the leading investigator-driven European NB clinical trial groups, SIOPEN and GPOH, with the goal of innovative ITH assessment in preclinical models and patient samples, application of new diagnostics and treatment algorithms targeting ITH in clinical trials.
Hypothesis: Analyses of tumour tissue and liquid biopsies by advanced genomic, expression and epigenomic techniques will generate a more complete picture of spatial/temporal ITH and support an individualised therapeutic strategy based on the most aggressive and druggable tumour clone. Minimally invasive techniques will support monitoring for point mutations and disease load.
Aim: Development of new strategies to overcome tumour sampling error based on ITH, including i) establishing techniques to detect resistant clones in tumour tissue/liquid biopsies, ii) performing a systematic combined analysis of genomic/RNA/epigenetic changes in primary/metastatic patient samples, iii) establishing a robust technique for disease monitoring and detection of druggable mutations, iv) validating biomarkers in biological models and v) providing recommendations for the best strategies to molecularly diagnose/monitor disease for implementation into the next high-risk/relapse NB trial protocol.
Methods: The ONTHETRRAC consortium combines translational researchers with solid backgrounds in NB and specific expertise in whole genome/exome sequencing (WGS/WES), bisulfite sequencing, RNAseq, ChIPseq, miRNA and ncRNAs analyses, single-cell analyses and cell enrichment techniques.
Expected results & potential impact: ONTHETRRAC will advance understanding of molecular ITH in NB and firmly establish ITH issues in current diagnostic procedures and disease monitoring to enable the design of more effective treatment strategies taking all facets of the malignancy into account. The bundled unique expertise within ONTHETRRAC is best positioned to explore and validate relevant NB biomarkers and narrow the gap between understanding ITH in NB and applying current clinical methods for response and resistance with precision medicine approaches.