Spatial Distance Correlates With Genetic Distance in Diffuse Glioma.

Area of Science:

• Neuro-oncology
• Genomics
• Epigenetics

Background:

• Glioma patient prognosis is influenced by tumor-specific genetic and epigenetic factors.
• Intra-tumoral genetic heterogeneity presents a challenge in glioma management.
• Quantitative data on spatial genetic variation in gliomas is currently lacking.

Purpose of the Study:

• To quantitatively assess the relationship between physical distance and genomic distance within primary gliomas.
• To investigate if larger physical separations between tumor biopsies correlate with greater genetic diversity.
• To provide data supporting improved clinical diagnostic and therapeutic strategies for glioma.

Main Methods:

• Stereotactic biopsies were collected from untreated primary glioma patients.
• Physical distances between biopsy sites were calculated using imaging coordinates.
• Genomic distances were assessed using whole exome DNA sequencing, copy number variation (CNV) analysis, and epigenetic methylation profiling.

Main Results:

• A positive correlation was observed between physical and genomic distances across three distinct genomic measures.
• Correlation coefficients for gene-level mutations, CNV, and methylation status were 0.63, 0.65, and 0.35, respectively.
• Quantitative linear relationships between physical and genomic distances were established.

Conclusions:

• Primary brain gliomas exhibit significant genetic heterogeneity.
• Physical distance within a glioma correlates with genomic distance, validated by multiple genomic analyses.
• These findings can inform clinical practice by managing sampling error and estimating genetic heterogeneity using imaging data.