323 Background: Pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis due to late detection, aggressive biology and resistance to chemotherapy. Markers for early detection of PDAC and mediators of chemoresistance are poorly understood. GRP78 is a major endoplasmic reticulum (ER) chaperone protein critical for protein quality control of the ER. Increased GRP78 expression promotes in vitro cancer cell survival, progression, and chemoresistance. This study aims to examine expression of GRP78 protein in PDAC and intraductal papillary mucinous neoplasm (IPMN) compared to normal pancreatic ducts using immunohistochemistry (IHC). Methods: The expression of GRP78 was assessed using IHC in 93 sections of formalin-fixed paraffin-embedded tissue: normal ducts (38), low grade IPMN (IPMN-LG, 26), high grade IPMN (IPMN-HG, 9), and PDAC (20). Immunostaining intensity of GRP78 protein was categorized as no or weak staining (0-1+) and strong staining (2-3+). Fisher’s exact test with two tails was performed using the GraphPad statistical software. Results: GRP78 expression was identified in the cytoplasm of normal pancreatic ducts, IPMN and PDAC with a fine granular pattern. All PDAC and IPMN-HG showed strong expression of GRP78 while the normal ductal cells showed only minimal expression of GRP78. 73% of IPMN-LG expresses GRP78 strongly. Statistical analysis revealed a significant difference in GRP78 expression level between normal ductal cells and all three pathological conditions including PDCA, IPMN-HG and IPMN-LG (all p < 0.0001). Conclusions: This study shows that the expression level of GRP78 is significantly increased in PDAC, IPMN-HG and IPMN-LG compared to normal ductal cells. There appears to be a progressive increase in GRP78 expression from IPMN-LG to IPMN-HG and invasive PDAC. Increased GRP78 expression may be a marker for those at risk of developing PDAC. Changes in GRP78 expression over time and its role in PDAC chemoresistance should be further assessed. [Table: see text]
Pancreatic Ductal Adenocarcinoma Concomitant with Main Duct Type Intraductal Papillary Mucinous Neoplasm of the Pancreas: A Case Report