The significance of HPV status in patients with anal cancer: A comparative technical analysis.
Bibliographic record
Abstract
425 Background: HPV status is an important prognostic factor for outcome in head and neck cancers, with improved survival noted in HPV-positive vs -negative tumors. However, this effect has not been studied in anal cancer. Challenges exist in defining reliable and methods of detecting the presence of high-risk HPV virus or the expression of HPV-related proteins. Purpose: To determine p16 expression and HPV16 status, in association with HPV subtyping, in pre-treatment anal cancers, and to correlate marker status with clinical outcome. Methods: This retrospective study evaluated anal cancer patients treated between 1992-2005 with definitive RT or CRT at a single institution (Tom Baker Cancer Centre, Calgary, Canada). HPV subtyping, p16 protein expression via conventional immunohistochemistry (IHC) and automated quantitative IHC (AQUA), and HPV16 in-situ hybridization (CISH) was performed in a subset of patient tumors with sufficient pretreatment tumor specimen. The correlation between results using these different techniques and association of HPV markers with clinical outcome was evaluated. Results: 89 patients were identified; M:F 1:2; median age 57 years. Median tumor size was 3.5 cm. All patients were treated with radical external beam RT with curative intent; 81% received concurrent chemotherapy. Clinical CR was observed in 73% of patients at 3 months post-treatment. Median OS was 82 months. Of tumor specimens analyzed for HPV subtype, 78% (28/36) were HPV16. Using conventional IHC (DAB), 80% (28/35) of tumors over-expressed p16 (score 3). HPV16 CISH was positive in 81% (34/42). P16 AQUA™ score correlated with HPV16 subtyping, CISH for HPV16, and p16 DAB. With HPV16 subtyping as the gold standard for HPV16 infection, false positive and false negative rates were 8% and 4% with DAB, and 10% and 13% with CISH. In univariate analysis only p16 AQUA score > 244 (upper 15%) was associated with PFS (p= 0.006-95% CI 8.4 [1.8-38.6]) and OS (p= 0.013-95% CI 4.5 [1.4-15]). Conclusions: p16 expression via quantitative IHC correlates with other methods, including HPV16 subtyping, and appears more reliable for defining HPV16 status than CISH. Only quantitative IHC identified a subset of patients with worse outcome. No significant financial relationships to disclose.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 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 | 0.001 |
| 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".