title: Ephrin b2 receptor and microsatellite status in lymph node-positive colon cancer survival.
abstract: BACKGROUND
  Ephrin B2 receptor (EphB2) is a target of the canonical wnt pathway implicated in colorectal carcinogenesis, and its down-regulation may be associated with adverse prognosis. We evaluated its prognostic value in resected colon cancer stratified by microsatellite status and other clinicopathologic characteristics.
  
  
  METHODS
  We identified all cases of resected stage III colon cancer from 1995 to 2009 managed in the Capital Health district of Nova Scotia. Tissue microarrays were constructed and immunohistochemistry (IHC) for tumor EphB2 staining assigned into quartiles. Microsatellite status was evaluated by IHC for MutL homolog 1 (MLH1) and MutS homolog 2 (MSH2). Microsatellite stable tumors were defined as both MLH1/MSH2 (+/+); tumors staining otherwise were classified with microsatellite instability (MSI-H). Primary and secondary outcomes were disease-free survival (DFS) and overall survival (OS), respectively.
  
  
  RESULTS
  We identified 159 cases with sufficient tissue for microarray analysis having a median follow-up of 3.47 years (range, 0.14-14). Median age was 61, 52% were male, 40% had an event, and 29% died. MSI-H was present in 18 (13%). Univariate analysis of EphB2 expression on DFS and OS showed a hazard ratio (HR) of 2.00 (P = .01) and 2.14 (P = .03), respectively. Multivariate analysis of EphB2 expression on DFS and OS showed an HR of 2.24 and 2.23, respectively, with tumor IHC ≤ 50%.
  
  
  CONCLUSIONS
  In this cohort, decreased EphB2 expression was an independent prognostic factor for recurrence and death and may have prognostic relevance in tumors with MSI-H. However, this would require prospective validation in a larger study.
authors.affiliation: Capital Health and Department of Medicine, Division of Medical Oncology, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Arik
authors.initials: A
authors.lastname: Drucker
authors.forename: Thomas
authors.initials: T
authors.lastname: Arnason
authors.forename: Sen Rong
authors.initials: SR
authors.lastname: Yan
authors.forename: Mohammed
authors.initials: M
authors.lastname: Aljawad
authors.forename: Kara
authors.initials: K
authors.lastname: Thompson
authors.forename: Weei-Yuarn
authors.initials: WY
authors.lastname: Huang