title: Cytokeratin deposits in lymph nodes show distinct clinical significance from lymph node micrometastasis in human esophageal cancers.
abstract: BACKGROUND
  Cytokeratin immunostaining is the most common method used to identify micrometastatic cancer cells from the lymph nodes. However, contamination with hyalinized cytokeratin particles, frequently observed in the lymph nodes of esophageal cancer patients, can lead to misinterpretation of cytokeratin immunostaining.
  
  
  METHODS
  Cytokeratin immunostaining (AE1/AE3) of surgically removed lymph nodes was performed for 41 cases of node-negative, but locally advanced (T3, T4), esophageal cancer patients. Cytokeratin immunoreactivity (CK) was classified as micrometastasis (MM) or cytokeratin deposit (CD) by the presence or absence of tumor nuclei in serial sections given hematoxylin-eosin staining.
  
  
  RESULTS
  CK (+) was observed in 18 patients (44%), including 11 with MM (+) (27%) and 10 with CD (+) (24%). There was no correlation between MM and CD, and neither was associated with clinicopathological factors, except for a high incidence of preoperative chemotherapy in CD (+) patients. The presence of CK did not affect postoperative survival of esophageal cancer patients at this limited stage, showing a 5-year survival rate of 57% for CK (+) and 64% for CK (-) (P = 0.6064). Interestingly, patients with MM (+) showed poorer prognosis than MM (-) (5-year survival: 28% vs 79%, P = 0.0188), while CD (+) patients tended to display better prognosis than CD (-) ones (5-year survival: 78% vs 56%, P = 0.1860).
  
  
  CONCLUSIONS
  Evaluation by cytokeratin immunostaining of lymph nodes requires careful discrimination of CD from MM, in order to allow MM to be used as a prognostic factor for esophageal cancer patients.
authors.affiliation: Department of Surgery, Osaka Medical Center for Cancer and Cardiovascular Diseases, Japan.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Doki
authors.forename: Osamu
authors.initials: O
authors.lastname: Ishikawa
authors.forename: Masayuki
authors.initials: M
authors.lastname: Mano
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hiratsuka
authors.forename: Yo
authors.initials: Y
authors.lastname: Sasaki
authors.forename: Masao
authors.initials: M
authors.lastname: Kameyama
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Ohigashi
authors.forename: Kohei
authors.initials: K
authors.lastname: Murata
authors.forename: Terumasa
authors.initials: T
authors.lastname: Yamada
authors.forename: Isao
authors.initials: I
authors.lastname: Miyashiro
authors.forename: Shigekazu
authors.initials: S
authors.lastname: Yokoyama
authors.forename: Shingo
authors.initials: S
authors.lastname: Ishiguro
authors.forename: Shingi
authors.initials: S
authors.lastname: Imaoka
mesh_terms: D004938:Esophageal Neoplasms / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000378:metabolism*; D008198:Lymph Nodes / Q000378:metabolism*; D008207:Lymphatic Metastasis / Q000473:pathology*; D011379:Prognosis
chemical_list: D007633:Keratins