[639] Expression of S100p in Human Esophageal Adenocarcinoma and Its Precursor Lesions

W Feng, Z Zhou, D Tan. The University of Texas Medical School at Houston, Houston; University of Rochester Medical Center, Rochester; The University of Texas M.D. Anderson Cancer Center, Houston

Background: S100p is a 95-amino acid protein with a restricted cellular distribution that was first purified from placenta. It has been shown to be expressed in prostate adenocarcinoma and gastrointestinal malignancies, such as colon and pancreatic adenocarcinoma. It is also a poor prognostic factor for lung and breast cancer. The expression of S100p in esophageal adenocarcinoma (EAC) and its precursor lesions, including distinctive-type Barrett mucosa (BM) (intestinal metaplasia) and esophageal columnar dysplasia (ECD) is largely unknown. Therefore, in this study, we evaluated the expression of S100p in EAC and its precursor lesions.
Design: We examined samples from 135 cases of esophageal adenocarcinoma, 40 ECD (15 high grade and 25 low grade), 37 BM without dysplasia, and 164 non-neoplastic esophageal mucosa (NNEM) without dysplasia or BM, in formalin-fixed, paraffin-embedded tissue microarray blocks. Tissues were stained with antibody against S100P (1:20, MAB2957, R&D Systems) and incubated for 30 minutes at ambient temperature. The intensity (1-3+) and percentage of positive nuclear-staining cells were determined, and a composite score (CS), the product of the intensity and percentage of positive cells (0-300) was calculated. The significance of difference in means was determined by two-tailed student's t-test.
Results: Some EAC cases (48 of 135 [36%]) showed 1-3+ nuclear S100p staining. Poorly differentiated EAC had statistically significant lower S100p expression than did well and moderately differentiated EAC (p<0.001). Furthermore, patients with high S100p-expressing EAC (76% one year survival) had better survival than did those with low S100p-expressing EAC (56% one year survival)(p=0.06). A subset of ECD cases (23 of 40 [64%]), including 14 low grade dysplasia and 9 high grade dysplasia cases showed weak 1+ staining for nuclear S100p. NNEM without BM (53 of 164 [32%]) and NNEM with BM (27 of 37 [73%]) showed weak 1+ staining for S100p within the superficial columnar epithelium.
Conclusions: In this study, we showed that S100p is overexpressed in EAC, ECD, and columnar epithelium with and without distinctive-type BM. These results suggest that S100p overexpression plays a role in EAC carcinogenesis and is a prognostic marker for EAC.
Category: Gastrointestinal

Wednesday, March 24, 2010 9:30 AM

Poster Session V # 80, Wednesday Morning

 

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