title: Validation of intra-operative detection of paratracheal lymph node metastasis using real-time RT-PCR targeting esophageal squamous cell carcinoma.
abstract: BACKGROUND
  We previously reported that there was a significant correlation between paratracheal lymph node (LN) metastasis and cervical LN metastasis in thoracic esophageal squamous cell carcinoma (ESCC) patients. The purpose of this study was to establish an intra-operative detection method of LN micrometastasis (MM) of ESCC using hematoxylin-eosin (HE) staining, immunohistochemistry (IHC) and real-time RT-PCR with a Light Cycler technique, and to evaluate which method, or combination of methods, is most suitable for intra-operative detection of paratracheal LN MM.
  
  
  METHODS
  Under informed consent, we obtained 33 dissected paratracheal LN samples from 22 operative patients with ESCC. Afterwards, one LN was separated into three parts by a sharp razor, and each part was checked for metastasis by HE staining, IHC with anti-cytokeratin antibody and real-time RT-PCR for SCC mRNA with a Light Cycler.
  
  
  RESULTS
  It took 3 h for detection by real-time RT-PCR, while it took 2 h by IHC. The detection rates of MM by HE staining, IHC and real-time RT-PCR were 50.0, 33.3 and 83.3%, respectively. However, there was a case of false negative detection that was not detected by IHC or PCR.
  
  
  CONCLUSIONS
  The real-time RT-PCR method was useful for intra-operative detection of paratracheal LN metastasis. However, combination analysis of HE staining, IHC and real-time RT-PCR may be desirable because there was a case of false negative detection by IHC and real-time RT-PCR.
authors.affiliation: Department of Surgery and Surgical Basic Science, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Shiro
authors.initials: S
authors.lastname: Nagatani
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Shimada
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Li
authors.forename: Junichi
authors.initials: J
authors.lastname: Kaganoi
authors.forename: Takatsugu
authors.initials: T
authors.lastname: Kan
authors.forename: Masato
authors.initials: M
authors.lastname: Maeda
authors.forename: Go
authors.initials: G
authors.lastname: Watanabe
authors.forename: Masayuki
authors.initials: M
authors.lastname: Imamura
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000556:secondary* / Q000601:surgery; D002453:Cell Cycle; D004938:Esophageal Neoplasms / Q000473:pathology* / Q000601:surgery; D006416:Hematoxylin; D006801:Humans; D007150:Immunohistochemistry; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*; D013194:Staining and Labeling
chemical_list: D006416:Hematoxylin