Epigenetic differences between human papillomavirus-positive and -negative oropharyngeal squamous cell carcinomas.
Bibliographic record
Abstract
BACKGROUND: Epigenetic modifications are defined as heritable changes in gene expression that are not encoded in deoxyribonucleic acid (DNA). Despite the importance of epigenetics in tumorigenesis, there is a paucity of information regarding the epigenetic profiles of oropharyngeal squamous cell carcinoma (OPSCC). OBJECTIVE: The objective of this study was to identify epigenetic signatures associated with human papillomavirus (HPV)-positive and -negative OPSCC. METHODS: We collected demographic, pathologic, and survival data from 44 patients with advanced-stage OPSCC treated with surgery and chemoradiation at the University of Alberta between January 2006 and December 2008. Tumour specimen from these patients were retreived and sectioned for immunohistochemical analysis. Double immunofluorescence staining was performed with p16 (HPV surrogate) and a panel of epigenetic markers, namely, histone methyl-lysines 4, 9, and 27 and H4 methyl-lysine 20. Correlation between p16 and epigenetic markers was measured using Metamorph and Image J software. RESULTS: Forty-one percent of patients were p16 positive. No statistically significant differences were found between p16-positive and -negative patients in terms of age at diagnosis, tumour subsite, or smoking history. We found significant differences in histone methylation between p16-positive and -negative tumours. OPSCC tumours positive for p16 had global elevations of histone H4 monomethylated lysine 20 (H4K20me1) and H3 trimethylated lysine 27 (H3K27me3) with depletions of H4 trimethylated lysine 20 (H4K20me3). In contrast, p16-negative tumours had depleted levels of H4K20me1 and H3K27me3 with high levels of H4K20me3. CONCLUSIONS: HPV-positive and -negative OPSCCs have distinct epigenetic profiles representing broad gene expression differences between these tumours.
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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 | 0.000 |
| 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) | 0.002 | 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".