ONTHETRRAC

Project Coordinator

Peter Ambros
- St. Anna Kinderkrebsforschung/Solid Tumours
- Vienna, Austria

Project Partners

Gudrun Schleiermacher
- Institut Curie Département d'Oncologie Pédiatrique et INSERM U830
- Paris, France
Angelika Eggert
- Charité - Universitätsmedizin Berlin, Department of Pediatric
- Berlin, Germany
Frank Westermann
- Deutsches Krebsforschungszentrum DKFZ, Department of Neuroblastoma Genomics
- Heidelberg, Germany
Frank Speleman
- Ghent University Center for Medical Genetics, CMGG
- Gent, Belgium

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.

Neuroblastoma (NB) remains a deadly disease for 60% of high-risk patients. Existing molecular classifiers/drug targets stem from single biopsies of bulky tumors, but this simplified view of NB homogeneity is inappropriate. Intratumor heterogeneity (ITH) must be taken into account for predictive biomarker identification. ONTHETRRAC has assembled an international expert team in NB molecular genetics and clinical research, and build on their recent discoveries that NBs are both spatially and temporally heterogeneous, including intratumor, primary tumor/distant metastasis and diagnosis/relapse comparisons. We will invest cutting-edge omics and liquid biopsy technologies to develop strategies overcoming ITH-based sampling inaccuracy and support in-depth predictive biomarker analyses. Clonal evolution and disease progression simulated in mouse and zebrafish models will support biomarker validation. ONTHETRRAC aims to provide clinically relevant recommendations for how to molecularly diagnose and monitor disease course on the sub(clonal) level, taking spatial and temporal ITH into account. The resulting diagnostics and monitoring guidelines will be most valuable to guide new targeted therapeutic interventions and will directly be integrated into the next European high-risk and relapse NB trial protocols by partners participating in SIOPEN and GPOH trial planning boards, covering 99% of high-risk NB patients treated in Europe. ONTHETRRAC has the power to generate a more complete picture of spatial/temporal ITH, thereby supporting individualized therapeutic strategies targeted to the most aggressive and resistant tumor clone. Minimally invasive techniques will improve the feasibility of monitoring mutations and disease load during treatment. We propose a highly innovative approach for the scientific foundation necessary for a paradigm shift from diagnostic single-biopsy use towards multiple tumor and liquid biopsies for NB clinical care.