title: Gastric neuroendocrine carcinoma: clinicopathologic review and immunohistochemical study of E-cadherin and Ki-67 as prognostic markers.
abstract: OBJECTIVE
  Gastric neuroendocrine carcinoma (NEC) is an uncommon cancer of the stomach. The classification of NEC and its clinical behavior remains controversial, and prognostic markers and their therapeutic guidelines have not been clearly defined. The aim of this study was to evaluate the clinicopathologic characteristics of these tumors and analyze the expression of E-cadherin and Ki-67 as prognostic markers in gastric NECs.
  
  
  METHODS
  We retrospectively reviewed 17 cases of gastric NECs. Tumor pathology was reviewed and the tumors were categorized as well-differentiated NEC (n = 5) and poorly differentiated NEC (n = 12) according to the WHO classification. With the aim of evaluating the expression of E-cadherin and Ki-67 and their prognostic role in gastric NEC, immunohistochemical analysis of the tumors was performed.
  
  
  RESULTS
  The median survival of patients was 20.0 months (95% confidence interval (CI), 13.2-28.8). There was a statistically significant difference in overall survival between well and poorly differentiated NECs (P = 0.021). However, there was no significant difference in overall survival between patients with poorly differentiated small cell and large cell NEC (P = 0.796). Loss of E-cadherin was correlated with lymph node metastasis (P= 0.044). A high Ki-67 proliferation index (PI) (>60%) was correlated with tumor recurrence (P = 0.013) and histologic differentiation (P= 0.028).
  
  
  CONCLUSIONS
  Loss of E-cadherin may predict lymph node metastasis in gastric NECs. A high Ki-67 PI (>60%) could be used as a prognostic marker to predict aggressive gastric NECs in addition to standard pathologic classification.
authors.affiliation: Department of Surgery, Korea University College of Medicine, Seoul, Korea.
authors.forename: Yoon-Jung
authors.initials: YJ
authors.lastname: Boo
authors.forename: Sung-Soo
authors.initials: SS
authors.lastname: Park
authors.forename: Jong-Han
authors.initials: JH
authors.lastname: Kim
authors.forename: Young-Jae
authors.initials: YJ
authors.lastname: Mok
authors.forename: Seong-Joo
authors.initials: SJ
authors.lastname: Kim
authors.forename: Chong-Suk
authors.initials: CS
authors.lastname: Kim
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism*; D015820:Cadherins / Q000378:metabolism*; D018278:Carcinoma, Neuroendocrine / Q000378:metabolism* / Q000401:mortality / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000378:metabolism*; D008198:Lymph Nodes / Q000473:pathology; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D011379:Prognosis; D013274:Stomach Neoplasms / Q000378:metabolism* / Q000401:mortality / Q000473:pathology; D015996:Survival Rate
chemical_list: D014408:Biomarkers, Tumor; D015820:Cadherins; D019394:Ki-67 Antigen