ProEx C Immunostain as a Marker for Dysplasia in Barrett's Esophagus
GA Vincent, R Birbe, C Solomides, H Durra. Temple University Hospital, Philadelphia, PA
Background: ProEx C is an immunohistochemical stain containing monoclonal antibodies targeting the topoisomerase II-alpha and minichromosome maintenance protein 2, which are overexpressed in aberrant synthesis phase induction. Recent studies have validated this reagent as a marker for cervical dysplasia. Its usefulness in evaluating dysplasia in other tissues has not been extensively studied in the literature. The purpose of this study is to evaluate ProEx C as a marker for detecting and grading dysplasia in Barrett's esophagus, the main risk factor for developing distal esophageal adenocarcinoma.
Design: A retrospective analysis and immunostaining with ProEx C (BD Diagnostics, Burlington) were performed on 48 esophageal biopsy and resection specimens of Barrett's esophagus (17 negative for dysplasia, 12 indefinite, 9 low-grade, 10 high-grade dysplasia). Nuclear staining in the lower two-thirds of the metaplastic glands was considered negative. A positive stain was defined as nuclear staining extending to the upper third and surface epithelial cells (SECs) of the metaplastic glands. The positive stain was further classified as rare, focal strong, or diffuse strong. A statistical analysis was performed.
Results: Results are summarized in the following table:
|(%)||Rare (%)||Focal Strong (%)||Diffuse Strong (%)||Total (%)|
|No Dysplasia||15/17 (88)||1/17 (6)||1/17 (6)||0/17 (0)||2/15 (12)|
|Indefinite||4/12 (33)||5/12 (42)||3/12 (25)||0/12 (0)||8/12 (67)|
|Low-Grade||3/9 (33)||3/9 (33)||3/9 (33)||0/9 (0)||6/9 (67)|
|High-Grade||1/10 (10)||1/10 (10)||5/10 (50)||3/10 (30)||9/10 (90)|
Using dysplasia (indefinite, low-grade or high-grade) as an endpoint, ProEx C staining extending to the upper third and SECs of metaplastic glands in biopsy proven dysplasia yielded a sensitivity of 74% (23 of 31), a specificity of 88% (8 of 31), a positive predictive value (PPV) of 92% and a negative predictive value (NPV) of 65%. Using high-grade dysplasia as an endpoint yielded a sensitivity of 90% (9 of 10), a specificity of 58% (22 of 38), PPV of 36% and NPV of 96%.
Conclusions: The ProEx C immunohistochemical stain exhibits a high sensitivity (74%), specificity (88%), and PPV (92%) when used to identify and grade dysplasia in cases of Barrett's esophagus. When used in conjunction with routine histological analysis, ProEx C can be a valuable confirmatory test for identifying and grading dysplasia in Barrett's esophagus.
Wednesday, March 11, 2009 1:00 PM
Poster Session VI # 95, Wednesday Afternoon