Abstract 457: A comparison of IDH1 R132H [H09] and [IHC132] antibodies on diffuse gliomas
Bibliographic record
Abstract
Abstract Introduction In the 2016 World Health Organization Central Nervous System Tumor Classification, diffuse gliomas were reclassified to include astrocytic tumors (grade II and III), oligodendrogliomas (grade II and III), and grade IV glioblastomas with diffuse astrocytoma being distinct from the diffuse gliomas. This reclassification is due to the abundance of IDH1 mutations in many of these tumors. A much better outcome has been observed in these patients than those without this mutation. IDH1 mutation of the R132H type constitutes more than 90% of all IDH1 and IDH2 mutations. Further, IDH1 IHC is now widely applied for the differential diagnosis of these tumors. There are two distinct IDH1 R132H clones on the market, the H09 and IHC132. Comparing these markers for the IDH1 R132H mutations by IHC can help determine if one is superior for diagnostics. Materials and Methods IHC was performed on 3-5 um thick formalin-fixed, paraffin-embedded (FFPE) brain tissue arrays containing glioblastoma, astrocytoma, oligoastrocytoma, oligodendroglioma with adjacent normal tissue (US Biomax, Derwood, USA). These slides were deparaffinized, and peroxidase blocked in the usual manner. Slides were then subjected to HIER in a pressure cooker using a citrate-based buffer at 110°C for 15 minutes before being stained on a semi-automated instrument. The slides were stained with rabbit monoclonal IDH1 R132H antibody H09 (Dianova, Hamburg, Germany) and mouse monoclonal IDH1 R132H antibody IHC132 (GenomeMe, Richmond, Canada) at concentrations and protocols predetermined to match staining intensity. Results The mouse monoclonal anti-IDH1 R132H IHC132 has shown that it is analogous to the current IDH1 R132H [H09]. Upon review of the data, IHC132 marker stains a higher percentage of cases in glioblastoma compared to H09 (11%, n=36) and equal in astrocytoma (73%, n=15), oligoastrocytoma (75%, n=4), oligodendroglioma (100%, n=8). Neither clone stained normal brain tissue per negative controls. Conclusion Mouse monoclonal anti-IDH1 R132H [IHC132] compared with that of the rabbit monoclonal anti-IDH1 R132H [H09] showed equal sensitivity for astrocytoma, oligodendroglioma, and oligoastrocytomas with higher sensitivity for glioblastoma. The results provide evidence to support a higher percentage of positive staining and equal or greater intensity for clone IHC132 versus H09. Citation Format: Sara Figueroa, Joseph Vargas, Jason Ramos. A comparison of IDH1 R132H [H09] and [IHC132] antibodies on diffuse gliomas [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 457.
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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 | 0.001 | 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) | 0.004 | 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".