Quantitation of HER2/neu expression in primary gastroesophageal adenocarcinomas using conventional light microscopy and quantitative image analysis.
BACKGROUND
Human epidermal growth factor receptor 2 (HER2/neu) is overexpressed in a proportion of gastroesophageal (GE) adenocarcinomas, and trastuzumab treatment results in significant improvement in overall survival in patients with HER2/neu-overexpressing GE tumors. Grading of HER2/neu expression in GE tumors and its clinical application is different from that of breast cancer. HER2/neu immunohistochemistry (IHC) image analysis (IA), widely used in breast cancer, has not been studied in GE tumors.


OBJECTIVE
To evaluate the correlation between manual HER2/neu IHC scoring and HER2/neu IHC image analysis in GE adenocarcinomas with characterization of associated clinicopathologic features.


METHODS
Tumor grade, growth pattern, and stage were evaluated in 116 cases of primary GE adenocarcinoma biopsy and resection specimens. Using anti-HER2/neu antibody and the proposed HER2/neu scoring system for gastric cancer, HER2/neu IHC expression was recorded after manual scoring and automated IA interpretation.


RESULTS
HER2/neu overexpression (IHC 3+) was detected in 19% (10 of 54) of gastric tumors, and overall correlation between manual HER2/neu IHC interpretation and IA interpretation was 78% (42 of 54). HER2/neu overexpression (IHC 3+) was detected in 26% (16 of 62) of GE junction tumors, and the overall correlation between manual HER2/neu IHC interpretation and IA interpretation was 84% (52 of 62).


CONCLUSIONS
The HER2/neu IHC scoring system for GE adenocarcinomas differs from that of breast carcinoma. Automated IA, validated for scoring of HER2/neu IHC in breast cancer, has a low correlation between HER2/neu IHC 2+ and IHC 3+ cases scored by conventional light microscopy and cannot be reliably used in the interpretation of HER2/neu IHC expression in GE adenocarcinomas.
Department of Pathology, Immunology, and Laboratory Medicine, University of Florida College of Medicine, 1600 SW Archer Rd, Gainesville, FL 32610-0275, USA.
Jennifer
J
Jeung
Roshan
R
Patel
Lizette
L
Vila
Dara
D
Wakefield
Chen
C
Liu
D000230:Adenocarcinoma / Q000378:metabolism*; D066246:ErbB Receptors / Q000378:metabolism*; D004938:Esophageal Neoplasms / Q000378:metabolism* / Q000473:pathology; D004943:Esophagogastric Junction / Q000378:metabolism* / Q000473:pathology; D018734:Genes, erbB-2; D006801:Humans; D007150:Immunohistochemistry; D008853:Microscopy; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D012189:Retrospective Studies; D013274:Stomach Neoplasms / Q000378:metabolism* / Q000473:pathology
D066246:ErbB Receptors; D018719:Erb-b2 Receptor Tyrosine Kinases