Back to Annual Meeting Program

INTRODUCTION:
Epithelial Cell Adhesion Molecule (EpCAM) is a transmembrane glycoprotein expressed by human epithelial cells. EpCAM is known to be involved in cell-cell adhesion, proliferation, differentiation and apoptosis. The aim of this study was to evaluate the clinical predictors of EpCAM over-expression in patients with resected esophageal adenocarcinoma (EAC).

METHODS:
EpCAM expression was assessed using immunohistochemical (IHC) staining in patients undergoing esophagogastrectomy for EAC. EpCAM expression was classified as low (<10%), intermediate (11-60%), or high (>60%). EpCAM expression in malignant tissue was compared to expression in benign esophageal tissue harvested approximately 1-2 cm from the margin of the tumor. Age, gender, TNM stage at diagnosis, and presence of neoadjuvant therapy were evaluated as possible clinical predictors of increased EpCAM expression. Disease-free survival (DFS) and overall survival (OS) were evaluated.

RESULTS:
The median age of the patient population was 61 years. Pre-operative TNM stage distribution was n=3, n=4, and n= 6, for stages 1, 2, and 3 respectively. 62% of patients underwent neoadjuvant therapy. Low, intermediate, and high EpCAM expression in malignant tissue occurred in 61%, 31%, and 8% of patients respectively and in 77%, 23%, and 0% of benign adjacent tissue respectively. EpCAM expression in malignant tissue was not shown to be significantly higher than EpCAM expression in benign adjacent tissue (p=0.3). Clinical variables of age, TNM stage at diagnosis, and neoadjuvant therapy did not predict level of EpCAM expression (p=0.9, p=0.4, and p=0.6 respectively). Median DFS and OS were 12 months and 28 months respectively. DFS and OS did not correlate with EpCAM expression (p=0.6 and p=0.6 respectively). Median survival after recurrence was 1 month and did not correlate with EpCAM expression (p=0.6). Complete response to neoadjuvant therapy based on postoperative pathologic stage was associated with an increased level of EpCAM expression (p=.02).

CONCLUSION:
EpCAM expression is significantly increased in patients who have complete response to neoadjuvant therapy. Further evaluation is needed to better characterize the relationship between EpCAM over-expression and pathologic response to neoadjuvant therapy for EAC.