7f949318-1f26-471d-ac18-642813b5f8a7 - samples

Medulloblastoma intra-tumoural genetic heterogeneity and clonal evolution, and their role in disease pathogenesis and clinical behaviour, are poorly understood. We used single-cell whole-genome sequencing (sc-WGS) to reconstruct the natural history and temporal evolution of 14 medulloblastomas, representing its major clinico-molecular sub-classes. We identified wholly-clonal tumours which displayed single-clone expansion (i.e. linear evolution); all were observed in favourable-outcome sub-classes (i.e. MBWNT and infant MBSHH). In contrast, remaining tumours harboured sub-clonal structures which displayed punctuated or gradual trajectories; highest-risk sub-classes, typically characterised by MYC-amplification (MBGroup3) or TP53-mutation (MBSHH), and linked to genomic instability and LCA pathology, were most clonally-diverse. Clinically-adopted biomarkers were typically early-clonal/initiating events, representing exploitable targets for early-disease detection; in analyses of spatially-distinct tumour regions, a single biopsy was sufficient to assess their status. sc-WGS revealed events not previously appreciated in bulk tumour analysis, which arose later and/or sub-clonally and more commonly displayed spatial diversity; their clinical significance and role in disease evolution post-diagnosis now require establishment. In summary, our findings reveal diverse modes of tumour initiation and clonal evolution in the major medulloblastoma sub-classes, highlighting their pathogenic relevance and clinical potential.EGA dataset EGAD00001009057