The temozolomide O6-methylguanine-DNA methyltransferase (MGMT) study: A phase II trial to evaluate the effect of low-dose preoperative neoadjuvant temozolomide on brain tumour MGMT activity in glioma patients
Bibliographic record
Abstract
e13027 Background: Epigenetic methylation of the O6-methylguanine-DNA methyltransferase (MGMT) DNA repair gene promoter in tumor tissue from glioblastoma multiforme patients is associated with improved survival after treatment with radiotherapy plus concomitant and adjuvant temozolomide (TMZ). We hypothesized that MGMT promoter methylation mosaicism exists in glial tumors and would affect response to TMZ. Methods: This is a nonrandomized, prospective, open-label, two cohort, single-center phase II study. Twenty-three patients with brain tumors detected by MRI scan and suspected to be gliomas were evaluated. All eligible patients were treatment naive and were self-selected into a TMZ group or a control group. The primary goal of the study was to evaluate the effect of TMZ 75 mg/m2 daily prior to surgery on the brain tumor MGMT expression. Secondary endpoints included safety, tolerability, and MGMT promoter methylation mosaicism in glial tumors. Samples were obtained from multiple regions of each tumor intra-operatively and were analyzed by methylation specific PCR. Results: Our results on MGMT promoter methylation demonstrate that three groups of patients can be identified: Type I: all sites assessed in the tumor demonstrate no methylation of the MGMT promoter; Type II: all sites demonstrate high levels of MGMT promoter methylation; and Type III: a mixed promoter methylation pattern is observed. Conclusions: These results suggest that 1) preoperative neoadjuvant temozolomide is not associated with increased postoperative complications; 2) glial tumors can have very heterogeneous areas of MGMT promoter methylation; and 3) three patterns of MGMT promoter methylation can be discerned. This experimental paradigm may be a useful experimental platform for the assessment of the effect of new drugs at the tumor level. [Table: see text]
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
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".