PATH-21. INVESTIGATING CHANGES IN IDH MUTATION STATUS AT GLIOMA RECURRENCE
Bibliographic record
Abstract
Abstract PURPOSE Isocitrate dehydrogenase (IDH) mutation status is a key diagnostic and prognostic feature of gliomas. It is thought to occur early in glioma tumorigenesis and remains stable over time. We investigated our tumour bank to identify patients where IDH mutation status changed after glioma recurrence. METHODS We identified four patients with immunohistochemistry-recorded IDH mutation statuses that conflicted between multiple tumour samples taken over time. Tissue samples from the tumour bank were analyzed using methylation profiling and Sanger sequencing of IDH1 and IDH2 to verify IDH status. RESULTS In all four instances, we found that IDH mutation status in fact remained stable, and there were reasonable explanations as to why mutation status was misinterpreted. One tumour had a non-canonical IDH2 R172K mutation that is not routinely tested for. Two patients had perilesional samples, revealed by methylation profiling to contain a mixture of tumour and normal brain. One patient had a IDH wildtype sample with a methylation profile consistent with reactive brain tissue rather than tumour. CONCLUSIONS All four cases of IDH mutation change at glioma recurrence were due to either misinterpreting perilesional or reactive tissue as tumour or overlooking a non-canonical mutation. This finding supports the concept that IDH mutation is a fixed characteristic of gliomas and highlights the importance of accurate surgical biopsy and molecular testing at initial diagnosis.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".