Perturbations of the Ink4a/Arf gene locus in aflatoxin B1-induced mouse lung tumors
Bibliographic record
Abstract
Lung tumors from AC3F1 mice treated with aflatoxin B(1) (AFB(1)), were examined for loss of alleles, point mutations and hypermethylation of CpG sites within the promoters of the two genes in the Ink4a/Arf gene locus. Loss of microsatellite alleles in the Ink4a/Arf region occurred in 22 of 74 (30%) AFB(1)-induced lung tumors. Fifty-one of 61 (83%) tumors had at least partial methylation of CpG sites within the p16Ink4a promoter-exon 1alpha region. At least partial methylation of CpG sites was observed in 43 of 49 (88%) tumors analyzed for p19Arf promoter hypermethylation, with methylation of identified transcription factor binding sites or consensus sequences occurring in 21 tumors (DMP1/Ets in two tumors, CTCF in four tumors, E2F in three tumors, Sp1 in 16 tumors). Two tumors contained point mutations in the p19Arf promoter. Nuclear staining for p19(Arf) was decreased by 80-100% in 41 of 71 (58%) tumors. The concordance between p19Arf molecular perturbations and altered protein expression was 63%. However, upon comparing p19Arf promoter perturbations (i.e. methylation of functional transcription factor binding sites and point mutations) and altered p19(Arf) expression, the concordance was 86%, suggesting a mechanism for changes in protein expression in some tumors. There was an absence of a mutually exclusive relationship between disruption of p53 and p19(Arf), since the concordance was 62%. Similarly, no evidence was found of inverse relationships between perturbation of p16Ink4a and p19(Arf) (43% concordance) or p16Ink4(a) and p53 (37% concordance), suggesting that inactivation of these genes occurs independently and provides evidence that, although these genes may participate in cooperative cellular pathways, they also have functions in independent pathways that are important in mouse lung tumorigenesis.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 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) | 0.000 | 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 teacher head, 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".