CDX2, Cytokeratins 7 and 20 Immunoreactivity in Rectal Adenocarcinoma
Bibliographic record
Abstract
There are limited data regarding CDX2 expression in rectal carcinoma. The CK20/CK7 immunoprofile of colorectal adenocarcinoma has been described in studies, which have mostly lumped colonic and rectal tumors together. In this study, we investigated the diagnostic utility of immunohistochemical stains for CK7, CK20, and CDX2 in a series of rectal adenocarcinoma. Fifty-five specimens of rectal adenocarcinomas were retrieved and immunostained for CK7 (Dako-M7018), CK20 (NovoCastra NCL-L-CK20), and CDX2 (NovoCastra NCL-CDX2). Thirty cases of pancreatic adenocarcinoma and 15 cholangiocarcinomas were also studied as a comparison group. CK7 was expressed in 12/55 (22%) and CK20 in 48/55 (87%) cases of rectal adenocarcinoma. The CK7-/CK20+ immunophenotype was identified in 36/55 (65%), CK7+/CK20+ in 12/55 (22%), and CK7-/CK20- in 7/55 (13%) rectal adenocarcinoma. CDX2 showed moderate-strong positivity in all cases and was not related to tumor differentiation. Benign rectal mucosa was available in 37 cases and showed the following results: CK7-/CK20+ in 25/37 (67%), CK7+/CK20+ in 8/37 (22%) and CK7-/CK20- in 4/37 (11%) cases. In pancreatic adenocarcinomas and cholangiocarcinomas, 29/45 (64%) were CK7+/CK20+ and 16/45 (36%) were CK7+/CK20-. CDX2 was positive in only 3/45 (7%) of these cases; all were pancreatic adenocarcinomas. In conclusion, CK7 can be expressed in rectal adenocarcinoma, and should not be used as the sole basis for excluding a rectal primary. CDX2 is a sensitive marker for rectal origin of adenocarcinoma. It can be helpful in cases with metastatic rectal carcinoma, especially those with CK7+/CK20+ or CK20-/CK7- immunophenotype. In this study, CDX2 expression was not influenced by the grade (differentiation) of rectal adenocarcinoma.
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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 | 0.001 |
| 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 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".