# Data-driven probabilistic mapping of the spatial and molecular landscape of glioma

## TL;DR

This study creates probabilistic brain maps of glioma tumors using MRI data from over 2000 patients, linking tumor location to molecular subtypes, age, and survival rates.

## Contribution

The study introduces probabilistic radiologic maps of glioma locations, integrating spatial, molecular, and clinical data from a large multi-database cohort.

## Key findings

- Smaller gliomas are more common in the left temporal region, while larger ones are in frontotemporoparietal regions.
- IDH-mutant tumors are preferentially found in frontotemporal regions, while IDH-wild-type tumors are more common in medial parietotemporal regions.
- Tumors in medial structures and parietal lobes are associated with lower survival rates.

## Abstract

Understanding the spatial distribution of gliomas in the brain and their molecular subtypes can aid in the diagnosis and development of targeted therapies. This study aims to create probabilistic radiologic maps of glioma locations using large MRI datasets and the most recent consensus brain tumour classification. Neuroimaging data from multiple databases were analysed. Patients included had MRI T1 images and validated tumour segmentations. Probabilistic tumour maps were generated whereby binary tumour masks were aligned to a standard brain template and aggregated to compute voxel-wise frequency maps of glioma occurrence detailing glioma volume, molecular subtype, age, sex and overall survival with tumour location. The study included 2164 patients with gliomas. Key findings include distinct spatial patterns associated with glioma size and molecular subtype: smaller tumours favoured the left temporal region, medium-sized tumours the medial frontoparietal and bilateral temporal regions and larger tumours the frontotemporoparietal regions, predominantly on the right. Isocitrate dehydrogenase (IDH)-wild-type tumours were more common in medial parietotemporal regions, while IDH-mutant tumours were preferentially found in frontotemporal regions. Younger patients had more frontal tumours, while older patients had higher parieto-occipital tumour burdens. Tumours in medial structures and parietal lobes were linked to lower survival, whereas right temporal tumours were associated with higher rates of survival. These findings likely correlate with IDH mutation status. Leveraging eight glioma databases, probabilistic tumour maps revealed significant relationships between brain regions, molecular subtypes and clinical outcomes. These findings could be used in clinical decision-making and offer insights into glioma pathogenesis and treatment of patients impacted by this disease.

Samuel et al. report probabilistic brain maps of glioma derived from over 2000 patients across eight datasets. Tumour location was linked with molecular subtype, age and survival. These findings provide a large-scale resource to improve diagnosis, prognostication and understanding of glioma pathogenesis and treatment strategies.

Graphical Abstract