Clinical Utility of ERG Immunohistochemistry as a Vascular Marker with Assessment of Lymphovascular Invasion
Sehun Kim, Hyung Kyu Park, Ho Young Jung, So Dug Lim, Wook Youn Kim, Hye Seung Han, Tae Sook Hwang, Wan Seop Kim. Konkuk University Medical Center, Seoul, Republic of Korea
Background: ERG, member of the ETS family transcription factors is a highly specific vascular marker and the clinical utility of ERG immunohistochemistry (IHC) for assessing lymphovascular invasion (LVI) has not been studied yet. We investigated clinical utility of ERG immunohistochemistry (IHC) for assessing LVI relative to HE only or the previous vascular markers.
Design: In the first round review (FRR) of LVI, 15 cases of surgically resected colorectal cancers (CRCs) with lymph node and liver metastasis from the pathology archives were collected. HE stain and IHCs for ERG, CD31, and D2-40 were performed on each representative section for assessing LVI. First 6 pathologists independently evaluated LVI in HE only. Each combined HE & IHC slides were recirculated to reevaluate LVI. Finally consensus meeting was held and all participants reassessed LVI. After intensive discussion and education about assessing LVI in FRR, the second round review (SRR) of LVI with another 10 CRCs was performed. Results were analyzed by kappa(κ) statistics.
Results: In FRR, average κ values of HE only, CD31, D2-40, and ERG were 0.27, 0.55, 0.21, and 0.23 respectively. Agreement was moderate for CD31 IHC due to high negative rate (80%). Good agreement after consensus was observed for use of ERG IHC (κ=0.65) with high positive rate of LVI (80%). In SRR, better agreement with assessment of LVI using IHCs was observed relative to HE only (p<0.01).
Conclusions: We demonstrated a superiority of ERG IHC for the pathologists to recognize LVI relative to the histology only or use of the other markers. Our results prompt further validation study of its prognostic utility in various cancers and educational module with assessment of LVI.
Monday, March 4, 2013 1:00 PM
Poster Session II # 266, Monday Afternoon