Rapid brain tumor classification from sparse epigenomic data
Björn Brändl, Mara Steiger, Carolin Kubelt, Christian Rohrandt, Zhihan Zhu, Maximilian Evers, Gaojianyong Wang, Bernhard Schuldt, Ann‐Kristin Afflerbach, Derek A. Wong, Amy Lum, Skarphéðinn Halldórsson, Luna Djirackor, Henning Leske, Svetlana Magadeeva, Romualdas Smičius, Claudia Quedenau, Nils Ole Schmidt, Ulrich Schüller, Einar Osland Vik-Mo, Martin Proescholdt, Markus J. Riemenschneider, Gelareh Zadeh, Ole Ammerpohl, Stephen Yip, Michael Synowitz, Alena van Bömmel, Helene Kretzmer, Frank Müller
Abstract
Although the intraoperative molecular diagnosis of the approximately 100 known brain tumor entities described to date has been a goal of neuropathology for the past decade, achieving this within a clinically relevant timeframe of under 1 h after biopsy collection remains elusive. Advances in third-generation sequencing have brought this goal closer, but established machine learning techniques rely on computationally intensive methods, making them impractical for live diagnostic workflows in clinical applications. Here we present MethyLYZR, a naive Bayesian framework enabling fully tractable, live classification of cancer epigenomes. For evaluation, we used nanopore sequencing to classify over 200 brain tumor samples, including 10 sequenced in a clinical setting next to the operating room, achieving highly accurate results within 15 min of sequencing. MethyLYZR can be run in parallel with an ongoing nanopore experiment with negligible computational overhead. Therefore, the only limiting factors for even faster time to results are DNA extraction time and the nanopore sequencer's maximum parallel throughput. Although more evidence from prospective studies is needed, our study suggests the potential applicability of MethyLYZR for live molecular classification of nervous system malignancies using nanopore sequencing not only for the neurosurgical intraoperative use case but also for other oncologic indications and the classification of tumors from cell-free DNA in liquid biopsies.