Nuclear IMPDH Filaments in Human Gliomas

Area of Science:

• Neuro-oncology
• Cell Biology
• Molecular Pathology

Background:

• Nuclear morphology is crucial for glioma diagnosis and grading.
• Intranuclear rods (rods) were previously identified in ependymomas using an antibody against class III beta-tubulin (TUBB3).

Purpose of the Study:

• To investigate the prevalence and significance of nuclear rods in adult diffuse gliomas.
• To determine the antigenic properties and functional role of nuclear rods.

Main Methods:

• Analysis of nuclear rods in a cohort of adult diffuse gliomas (IDH-mutant and IDH-wildtype).
• Assessment of the association between nuclear rods, patient survival, and proliferation markers (Ki67).
• Immunohistochemical analysis for nucleotide synthesizing enzymes (IMPDH, cytidine triphosphate synthetase) and lamin B1.

Main Results:

• Nuclear rods were found in 71.1% of IDH-mutant lower-grade gliomas and 13.7% of IDH-wildtype glioblastomas (GBMs).
• Presence of nuclear rods correlated with longer survival in younger GBM patients (≤65) and was inversely related to the Ki67 proliferation index.
• Rods showed immunoreactivity for IMPDH and cytidine triphosphate synthetase, and rod-containing nuclei had reduced lamin B1, suggesting a link to senescence and nucleotide synthesis regulation.

Conclusions:

• Nuclear rods are a potential diagnostic and prognostic marker in adult diffuse gliomas.
• Rods may regulate nucleotide-synthesizing enzymes via sequestration, influencing glioma behavior.
• The SDL.3D10 antibody recognizes an unknown antigen in nuclear rods, not TUBB3.