[774] Utilization of Reciprocal Expression Pattern of CRABP2 and CDX-2 in Diagnosing Pancreatic Ductal Adenocarcinoma

Wenbin Xiao, Hong Hong, Amad Awadallah, Wei Xin. University Hospitals Case Medical Center, Case Western Reserve University, Cleveland, OH

Background: Distinguishing pancreatic ductal adenocarcinoma (PDAC) from extensive chronic pancreatitis can be histologically challenging. Molecular biomarkers with high sensitivity and specificity for PDAC have been rigorously searched with some success. CRABP2, a retinoid acid binding protein, shuffles retinoid acid from cytosol into the nucleus and forms a complex with nuclear retinoid acid receptor to facilitate transcriptional activities of retinoid acid. CDX-2 is a homeobox domain-containing transcription factor involved in intestinal development and is expressed in the nuclei of epithelial cells throughout the intestine. In the following study, we would like to investigate whether the expression patterns of CRABP2 and CDX-2 could help us to distinguish PDAC from benign and pre-cancerous pancreatic lesions.
Design: Formalin-fixed paraffin-embedded blocks from surgically resected PDAC were extracted from our surgical pathology archive. Polyclonal anti-CRABP2 and anti-CDX-2 were used and immunohistochemical staining was performed in our hospital diagnostic lab. The control groups include normal pancreatic tissue, chronic pancreatitis, and pancreatic intraepithelial neoplasia (PanIN) 1-3.
Results: No expressions of CRABP2 were detected in normal pancreatic parenchyma, ductal epithelium and chronic pancreatitis.

Table 1. Reciprocal expression of CRABP2 and CDX-2 in PDAC
 Normal ParenchymaNormal DuctsChronic PancreatitisPDACMetastatic PDAC
CRABP20/51(0)0/26 (0)0/54 (0)56/56 (100%)4/4 (100%)
CDX-27/7(100%)7/7 (100%)8/8 (100%)2/18 (11%)1/10 (10%)

In contrast, CRABP2 expression was universally detected in all PDACs. CRABP2 staining was also observed and progressively increased from PanIN 1 to 3. On the other hand, CDX-2 expression was readily detected in normal pancreatic parenchyma, ductal epithelium and chronic pancreatitis, but largely undetected in PDACs.
Conclusions: Our study demonstrates over-expression of CRABP2 and loss-of-expression CDX-2 in PDACs. The reciprocal changes of CRABP2 and CDX-2 are probably late events of pancreatic carcinogenesis, and it could be used as diagnostic markers to distinguish PDAC from benign pancreatic conditions.
Category: Gastrointestinal

Monday, March 4, 2013 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 122, Monday Morning


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