title: Sentinel node micrometastases have high proliferative potential in gastric cancer.
abstract: BACKGROUND
  The 6th edition of the TNM classification has recently defined "sentinel nodes (SN)," "micrometastasis," and "isolated tumor cells (ITC)." The present study examines the frequency and proliferative activity of such metastases with focus on the SNs of gastric cancer.
  
  
  METHODS
  We enrolled 133 patients with cT1-2 tumors (cT1: 104, cT2: 29) and mapped SNs. Lymph node metastases were examined by routine histology and by immunohistochemistry with anti-cytokeratin. We used the Ki-67 antibody to detect the primary tumor and lymph node metastases to evaluate proliferative activity.
  
  
  RESULTS
  The number of patients with SNs metastases and metastatic SNs was 19 and 52, respectively. The frequencies of macrometastasis, micrometastasis, and ITC were 48%, 25%, and 27%, respectively. Ki-67 expression in the tumor closely correlated with lymphatic invasion (P = 0.0001), venous invasion (P < 0.0001), and lymph node metastasis (P < 0.0001). Cells in 96% of macrometastases, 92% of micrometastases, and 29% of ITCs were Ki-67 positive.
  
  
  CONCLUSIONS
  We showed that micrometastasis and some ITCs in SNs had proliferative activity. We suggest that micrometastasis and ITCs should be removed, especially during SN navigation surgery, until their clinical significance is clarified.
authors.affiliation: Course of Advanced Therapeutics, Field of Oncology, Department of Surgical Oncology and Digestive Surgery, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan. y0810@m.kufm.kagoshima-u.ac.jp
authors.forename: Shigehiro
authors.initials: S
authors.lastname: Yanagita
authors.forename: Shoji
authors.initials: S
authors.lastname: Natsugoe
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Uenosono
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Kozono
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Ehi
authors.forename: Takaaki
authors.initials: T
authors.lastname: Arigami
authors.forename: Hideo
authors.initials: H
authors.lastname: Arima
authors.forename: Sumiya
authors.initials: S
authors.lastname: Ishigami
authors.forename: Takashi
authors.initials: T
authors.lastname: Aikou
mesh_terms: D002277:Carcinoma / Q000556:secondary* / Q000601:surgery; D002454:Cell Differentiation; D002455:Cell Division; D005743:Gastrectomy; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000378:metabolism; D019394:Ki-67 Antigen / Q000378:metabolism; D008197:Lymph Node Excision / Q000379:methods*; D008198:Lymph Nodes / Q000473:pathology* / Q000601:surgery; D008207:Lymphatic Metastasis; D021701:Sentinel Lymph Node Biopsy; D013274:Stomach Neoplasms / Q000473:pathology* / Q000601:surgery
chemical_list: D019394:Ki-67 Antigen; D007633:Keratins