ROBIN: A unified nanopore-based sequencing assay integrating real-time, intraoperative methylome classification and next-day comprehensive molecular brain tumour profiling for ultra-rapid tumour diagnostics

Background Advances in our technological capacity to interrogate brain tumour biology has led to the ever-increasing use of genomic sequencing in routine diagnostic decision making. Presently, brain tumours are routinely classified based on their epigenetic signatures, leading to a paradigm shift in diagnostic pathways. Such testing can be performed so rapidly using nanopore sequencing that results can be provided intraoperatively. This information greatly improves upon the fidelity of smear diagnosis and can help surgeons tailor their approach, balancing the risks of surgery with the likely benefit. Nevertheless, full integrated diagnosis may require subsequent additional assays to detect pathognomonic somatic mutations and structural variants, thereby delaying the time to final diagnosis. Methods Here, we present ROBIN, a tool based upon PromethION nanopore sequencing technology that can provide both real-time, intraoperative methylome classification and next-day comprehensive molecular profiling within a single assay. ROBIN uniquely integrates three methylation classifiers to improve diagnostic performance in the intraoperative setting. Findings We demonstrate classifier performance on 50 prospective intraoperative cases, achieving a diagnostic turnaround time under 2 hours and generating robust tumour classifications within minutes of sequencing. Furthermore, ROBIN can detect single nucleotide variants (SNVs), copy number variants (CNVs) and structural variants (SVs) in real-time, and is able to inform a complete integrated diagnosis within 24 hours. Classifier performance demonstrated concordance with final integrated diagnosis in 90% of prospective cases. Interpretation Nanopore sequencing can greatly improve upon the turnaround times for standard of care diagnostic testing, including sequencing, and is furthermore able to reliably provide clinically actionable intraoperative tumour classification. Funding The Jean-Shanks Foundation, the Pathological Society of Great Britain and Ireland, the British Neuropathological Society, and the Wellcome Trust.