title: ERG Immunohistochemistry as an Endothelial Marker for Assessing Lymphovascular Invasion.
abstract: BACKGROUND
  ERG, a member of the ETS family of transcription factors, is a highly specific endothelial marker. We investigated whether the use of ERG immunostaining can help pathologists detect lymphovascular invasion (LVI) and decrease interobserver variability in LVI diagnosis.
  
  
  METHODS
  Fifteen cases of surgically resected colorectal cancers with hepatic metastasis were selected and the most representative sections for LVI detection were immunostained with ERG, CD31, and D2-40. Eight pathologists independently evaluated LVI status on hematoxylin and eosin (H&E) and the corresponding immunostained sections and then convened for a consensus meeting. The results were analyzed by kappa (κ) statistics.
  
  
  RESULTS
  The average rate of LVI positivity was observed in 43% with H&E only, 10% with CD31, 29% with D2-40, and 16% with ERG. Agreement among pathologists was fair for H&E only (κ=0.27), D2-40 (κ=0.21), ERG (κ=0.23), and was moderate for CD31 (κ=0.55). Consensus revealed that ERG nuclear immunoreactivity showed better visual contrast of LVI detection than the other staining, with improved agreement and LVI detection rate (κ=0.65, LVI positivity rate 80%).
  
  
  CONCLUSIONS
  The present study demonstrated a superiority with ERG immunostaining and indicated that ERG is a promising panendothelial marker that might help pathologists increase LVI detection and decrease interobserver variability in LVI diagnosis.
authors.affiliation: Department of Pathology, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Korea.
authors.forename: Sehun
authors.initials: S
authors.lastname: Kim
authors.forename: Hyung Kyu
authors.initials: HK
authors.lastname: Park
authors.forename: Ho Young
authors.initials: HY
authors.lastname: Jung
authors.forename: So-Young
authors.initials: SY
authors.lastname: Lee
authors.forename: Kyueng-Whan
authors.initials: KW
authors.lastname: Min
authors.forename: Wook Youn
authors.initials: WY
authors.lastname: Kim
authors.forename: Hye Seung
authors.initials: HS
authors.lastname: Han
authors.forename: Wan Seop
authors.initials: WS
authors.lastname: Kim
authors.forename: Tae Sook
authors.initials: TS
authors.lastname: Hwang
authors.forename: So Dug
authors.initials: SD
authors.lastname: Lim
keywords: CD31; ERG; Endothelial marker; Immunohistochemistry; Lymphovascular invasion