Methylation of the BRCA1 promoter is associated with decreased BRCA1 mRNA levels in clinical breast cancer specimens
Bibliographic record
Abstract
Functional inactivation of BRCA1 is an important mechanism involved in breast cancer pathogenesis. Mutation is often responsible for BRCA1 inactivation in familial breast cancer, but is not responsible for the decreased levels of BRCA1 seen in a subset of sporadic breast cancer patients. To determine if aberrant cytosine methylation of the BRCA1 promoter is associated with decreased BRCA1 gene expression in human breast cancer, high resolution bisulfite sequence analysis was used to analyze the cytosine methylation status of the BRCA1 promoter in 21 axillary node negative breast cancer patients with known levels of BRCA1 expression. Aberrant cytosine methylation of the BRCA1 promoter was detected in three of 21 patient specimens. These three specimens also expressed the lowest levels of BRCA1. Results from this analysis show that aberrant cytosine methylation of the BRCA1 promoter is directly correlated with decreased levels of BRCA1 expression in human breast cancer, and suggest that epigenetic silencing may be one mechanism of transcriptional inactivation of BRCA1 in sporadic mammary carcinogenesis.
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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) | 0.001 | 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".