title: Molecular staging of lymph nodes from patients with esophageal adenocarcinoma.
abstract: OBJECTIVE
  This study was designed to evaluate molecular markers for the detection of micrometastasis in esophageal adenocarcinoma, define algorithms to distinguish positive from benign lymph nodes and to validate these findings in an independent tissue set and in patients with p(N0) esophageal adenocarcinoma.
  
  
  METHODS
  Potential markers were identified through literature and database searches. All markers were analyzed by quantitative reverse transcription (QRT)-PCR on a limited set of primary tumors and benign lymph nodes. Selected markers were further evaluated on a larger tissue set and classification algorithms were generated for individual markers and combinations. Algorithms were statistically validated internally as well as externally on an independent set of lymph nodes. Selected markers were then used to identify occult disease in lymph nodes from 34 patients with p(N0) esophageal adenocarcinoma.
  
  
  RESULTS
  Thirty-nine markers were evaluated, six underwent further analysis and five were analyzed in the external validation study. Two markers provided perfect classification in both the screening and validation sets, although parametric bootstrap analysis estimated 2% to 3% optimism in the observed classification accuracy. Several marker combinations also gave perfect classification in the observed data sets, and estimates of optimism were lower, implying more robust classification than with individual markers alone. Five of thirty-four patients with esophageal adenocarcinoma had positive nodes by multimarker QRT-PCR analysis and disease-free survival was significantly worse in these patients (P = 0.0023).
  
  
  CONCLUSIONS
  We have identified novel QRT-PCR markers for the detection of occult lymph node disease in patients with esophageal adenocarcinoma. The objective nature of QRT-PCR results, and the ability to detect occult metastases, make this an attractive alternative to routine pathology.
authors.affiliation: Department of Surgery, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Liqiang
authors.initials: L
authors.lastname: Xi
authors.forename: James D
authors.initials: JD
authors.lastname: Luketich
authors.forename: Siva
authors.initials: S
authors.lastname: Raja
authors.forename: William E
authors.initials: WE
authors.lastname: Gooding
authors.forename: Virginia R
authors.initials: VR
authors.lastname: Litle
authors.forename: Michael C
authors.initials: MC
authors.lastname: Coello
authors.forename: Sydney D
authors.initials: SD
authors.lastname: Finkelstein
authors.forename: Melissa L
authors.initials: ML
authors.lastname: Chestney
authors.forename: Rodney J
authors.initials: RJ
authors.lastname: Landreneau
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Hughes
authors.forename: Tony E
authors.initials: TE
authors.lastname: Godfrey
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D000951:Antigens, Neoplasm / Q000032:analysis / Q000235:genetics; D014408:Biomarkers, Tumor / Q000032:analysis / Q000235:genetics; D002272:Carcinoembryonic Antigen / Q000032:analysis / Q000235:genetics; D015815:Cell Adhesion Molecules / Q000032:analysis / Q000235:genetics; D000071858:Epithelial Cell Adhesion Molecule; D004938:Esophageal Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D007381:Intermediate Filament Proteins / Q000032:analysis / Q000235:genetics; D053554:Keratin-20; D053552:Keratin-7; D007633:Keratins / Q000032:analysis / Q000235:genetics; D008198:Lymph Nodes / Q000737:chemistry / Q000378:metabolism / Q000473:pathology*; D008207:Lymphatic Metastasis; D008840:Microfilament Proteins / Q000032:analysis / Q000235:genetics; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D012334:RNA, Neoplasm / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D016019:Survival Analysis
chemical_list: D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D002272:Carcinoembryonic Antigen; D015815:Cell Adhesion Molecules; C499379:EPCAM protein, human; D000071858:Epithelial Cell Adhesion Molecule; D007381:Intermediate Filament Proteins; C507499:KRT20 protein, human; C507497:KRT7 protein, human; D053554:Keratin-20; D053552:Keratin-7; D008840:Microfilament Proteins; D012334:RNA, Neoplasm; C026615:villin; D007633:Keratins