Specific Intratumoral Microbiome Signatures in Human Glioblastoma and Meningioma: Evidence for a Gut-Brain Microbial...

Area of Science:

• Microbiology
• Oncology
• Genomics

Background:

• Brain tumors (BTs), including glioblastoma (GBM) and meningioma (MGM), represent a significant global health challenge.
• The gut microbiome's influence on cancer is recognized, but its specific role in BTs is largely unexplored.
• Understanding the intratumoral microbiome (ItM) is crucial for elucidating BT pathogenesis.

Purpose of the Study:

• To characterize the gut microbiota (GM) and ItM in patients with GBM and MGM.
• To compare microbial profiles between BT patients and healthy controls (HCs).
• To investigate the relationship between GM and ItM and its potential clinical implications for BT management.

Main Methods:

• 16S rRNA gene sequencing was employed to analyze the GM and ItM from fresh tissue samples.
• Samples were collected from 9 GBM patients, 18 MGM patients, and 12 age- and sex-matched HCs.
• Bioinformatic analyses included diversity assessments, differential abundance testing, and Venn analyses.

Main Results:

• BT patients exhibited reduced GM alpha diversity and distinct microbial communities compared to HCs, with notable enrichment of Verrucomicrobiota and Synergistaceae, and depletion of Lachnospiraceae and Peptostreptococcaceae.
• GBM and MGM showed specific GM alterations: GBM patients had reduced Peptostreptococcaceae and Eubacterium hallii group, while MGM patients had increased Synergistia and Erysipelatoclostridium.
• ItM profiling revealed distinct compositions: GBM tissues were enriched in Proteobacteria, Actinomycetota, and Campylobacterota, harboring Burkholderia-Caballeronia-Paraburkholderia, Helicobacter, and Leifsonia.
• MGM tissues showed higher levels of Bacillota and Bacteroidota, dominated by Bacteroides and Blautia.
• Significant overlap was observed between GM and ItM in both GBM (91 genera) and MGM (105 genera).

Conclusions:

• The gut and intratumoral microbiomes are significantly altered in brain tumor patients.
• Distinct microbial signatures differentiate GBM from MGM, and from healthy controls.
• The shared microbial genera between gut and tumor suggest a potential link influencing BT development and offering avenues for novel therapeutic strategies.