Rapid spatial molecular insights into human brain tumors by axial MALDI TOF mass spectrometry imaging

Importance of the Topic

MALDI mass spectrometry imaging combines untargeted molecular profiling with spatial resolution, offering a powerful complement to traditional histopathology in brain tumor diagnostics. By mapping lipids and glycans directly in tissue sections, this approach addresses the need for rapid, comprehensive molecular insights that align with precision medicine goals.

Study Objectives and Overview

This study aimed to evaluate axial MALDI TOF imaging for distinguishing disseminated medulloblastoma metastases from healthy spinal cord tissues. Using both lipid and N-glycan profiles, the work demonstrates how rapid, unbiased molecular imaging can identify tumor regions and underlying biochemical differences in fresh-frozen and FFPE specimens.

Methodology

Fresh-frozen and FFPE sections of spinal cord harboring medulloblastoma metastases were prepared on conductive slides. Lipid analysis employed DHB matrix applied via an M3+ sprayer, acquiring data in the 500–1100 m/z range. For N-glycan profiling, enzymatic release with PNGase F was followed by CHCA matrix deposition and imaging in the 900–4000 m/z window. All acquisitions used positive ion mode at 20 µm pixel size. Post-imaging H&E staining and digital microscopy provided anatomical reference. Data processing and unsupervised Probabilistic Latent Semantic Analysis (pLSA) were performed with SCiLS Lab 2025b to extract tissue-specific molecular components.

Used Instrumentation

• neofleX Imaging Profiler (Bruker) for axial MALDI TOF acquisitions
• M3+ sprayer (HTX Technologies) for matrix deposition
• Optical microscopy for post-MALDI H&E imaging
• SCiLS Lab 2025b software for spectral analysis and pLSA

Main Results and Discussion

Unsupervised pLSA of lipid images separated three distinct components corresponding to white matter, gray matter/infiltration zones, and disseminated medulloblastoma. A total of 190,153 pixels were acquired over an 8.7×8.7 mm² area at 20 pixels/second (≈ 2.6 hours total). Parallel N-glycan imaging yielded congruent clustering, further validating tumor boundaries. High-resolution maps revealed that lysophosphatidylcholine (LPC) 16:0 accumulates specifically in large anterior horn motor neurons, highlighting cell-specific lipid distributions.

Benefits and Practical Applications

This axial MALDI TOF approach provides:

• Rapid, label-free molecular mapping without the need for targeted assays
• High spatial resolution (20 µm) for cellular-level analysis
• Unbiased lipid and glycan profiling to delineate tumor margins
• Compatibility with both fresh-frozen and FFPE workflows

These attributes make it a valuable tool for research on tumor microenvironments, neurodegeneration studies, and potential intraoperative diagnostics.

Future Trends and Potential Applications

Advances may include integration with AI-driven data analytics, multimodal imaging platforms combining MALDI with optical or MRI modalities, and higher throughput instrumentation for clinical settings. Expanding to other cancer types and neurological disorders could further enhance molecular pathology and personalized treatment strategies.

Conclusion

Axial MALDI TOF imaging on the neofleX platform enables rapid, high-resolution lipid and glycan mapping that effectively distinguishes medulloblastoma metastases from normal spinal cord tissues. This methodology promises to accelerate translational research and foster more precise diagnostic workflows.

References

No external literature references were provided in the original text.