Molecular detection of lymph node micrometastases in colorectal cancer patients
Notice bibliographique
Résumé
A53 Objective: The clinical significance of lymph node micrometastases detected by immunological and molecular methods in node-negative colorectal cancer patients remains to be confirmed. In this study we compared the sensitivity of detection methods based on the transcriptional expression of several epithelial cell-specific genes in paraffin-embedded mesenteric lymph nodes, and assessed survival outcomes. Methods. Each block contained a variable number of nodes. RNA was extracted from 2 serial sections (20 μm each) and submitted to reverse transcription (RT). One seventh of cDNA was PCR amplified for 40 cycles at 60C, using gene-specific primers. Products were resolved by polyacrylamide gel electrophoresis with a DNA mass ladder for quantitation. RNA integrity was verified by amplifying the GAPDH and selenoprotein P housekeeping genes.To estimate the relative number of metastatic cells present in lymph nodes a calibration curve was established by serial dilutions of total RNA from HCT116 cells (10 picog per cell equivalent) followed by RT-PCR. The lowest detection limits were 2, 15-30 and 60 cells for CEA, EZH2 and PRL3 respectively.The study group included 44 patients, 98 blocks and 437 lymph nodes;144 from 18 stage I patients; 124 from15 stage II; 119 from 7 stage III and 50 from 4 stage IV patients. On average 10 nodes were dissected per patient. Fifteen nodes (12.5%) of stage III cases and 7 nodes (14%) of stage IV were identified by hitopathology. Results. Several genes, always expressed in lymph nodes, proved unsuitable markers of micrometastases:cytokeratins (CK20), the CDX2 homeobox gene, osteopontin, decorin. MUC2 was weakly expressed in the nodes of 6 patients (14%). Carcinoembryonic antigen (CEA), enhancer of zeste (EZH2), and the tyrosine phosphatase PRL3 were differentially expressed. EZH2 was always co-expressed with either CEA or PRL3. EZH2-expressing cells were found in 6% of stage I patients but in >30% of stage II, III and IV patients. The proportion of cases with an estimated >50 PRL3-expressing cells per 10,000 node cells increased from 44% (8/18) for stage I, to 87% (13/15, stage II), 86% (6/7, stage III) and 75% (3/4, stage IV). Likewise, the proportion of cases with an estimated >10 CEA-expressing cells per 10,000 node cells increased from 22% in stage I, to 60% (stage II), to 71% (stage III). The proportion of cases in which CEA and PRL3 were highly co-expressed in lymph nodes also increased from 22% (stage I) to >70% in advanced stages.Three of 7 stage III (43%) and 3 of 4 stage IV patients (75%) succumbed to distant metastases within less than 5 years after surgery. All had received chemotherapy. In all 6 cases, high proportions of either CEA-(3 cases) or PRL3-expressing cells (5 cases) or both (3 cases) were found in their lymph nodes. The ability of the CEA and EZH2 assays to predict the outcome of node-negative patients is based on the findings that: (i) The single stage I patient who succumbed to the disease after 5 years demonstrated undetectable CEA and PRL3 cells in lymph nodes.The median follow up time of 12 other stage I patients, who expressed CEA alone (6), PRL3 alone (2), both CEA and PRL3 (2) and no marker was 55 months. (ii) Five of 15 stage II patients (33%) died between 11 months and 6 years after surgery, 2 of unrelated cancers.They all expressed either CEA, PRL3 or both (3cases) in lymph nodes. Eleven of 15 stage II patients (73%) highly co-expressed CEA and PRL3 in lymph nodes. Three of 11 (27%) succumbed to the disease. Conclusions. We conclude that CEA, PRL3 and EZH2-expressing cells are detectable in lymph nodes in amounts and frequencies consistent with the staged progression of the disease. A higher proportion of stage II-III than stage I cases co-express CEA and PRL3 in lymph nodes.High expression of either CEA, PRL3 or both may account for about 30% of stage II patients with poor prognosis and is not predictive of poor outcomes for stage I patients.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,001 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».