title: Osteopontin expression is associated with improved survival in patients with pancreatic adenocarcinoma.
abstract: BACKGROUND
  Osteopontin (OPN) is a secreted protein of the extracellular matrix. It has been used as a marker for tumor aggressiveness and correlated with clinical outcomes in several solid tumors, such as liver, lung, and breast. We determined the OPN expression and its influence on survival in patients with resected pancreatic adenocarcinoma.
  
  
  METHODS
  Tissue microarrays were constructed from 245 resected pancreatic adenocarcinomas. Immunohistochemical staining for OPN was undertaken and compared to normal pancreas (n = 12). OPN expression was then correlated with patient demographics, tumor size, grade, node, and margin status. Survival curves were created by the Kaplan-Meier method and compared by log rank analysis.
  
  
  RESULTS
  In total, 181 (74 %) of pancreatic adenocarcinoma tissues expressed OPN compared to 7 (58 %) of normal controls (p = 0.004). Expression was observed predominantly in the cytoplasm of the tumor cells. The median and 2 year overall survival was longer when OPN was expressed (17.1 vs. 11.6 months, and 38 vs. 24 %, respectively, p = 0.04). Multivariate analysis showed OPN expression and T stage to be independent predictors of overall survival, while other histopathologic factors such as tumor grade, tumor size, and nodal status were not.
  
  
  CONCLUSIONS
  These results suggest that the presence of OPN expression in pancreatic adenocarcinoma may have a protective effect independent of tumor stage. This emphasizes the importance of the interaction between pancreatic cancer cells and their stromal elements.
authors.affiliation: Department of Surgery, The Ohio State University, Columbus, OH, USA.
authors.forename: Amy L
authors.initials: AL
authors.lastname: Collins
authors.forename: Jonathan
authors.initials: J
authors.lastname: Rock
authors.forename: Lavina
authors.initials: L
authors.lastname: Malhotra
authors.forename: Wendy L
authors.initials: WL
authors.lastname: Frankel
authors.forename: Mark
authors.initials: M
authors.lastname: Bloomston
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism* / Q000401:mortality* / Q000556:secondary; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007124:Immunoenzyme Techniques; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D053495:Osteopontin / Q000378:metabolism*; D010190:Pancreatic Neoplasms / Q000378:metabolism* / Q000401:mortality* / Q000473:pathology; D011379:Prognosis; D015996:Survival Rate; D046888:Tissue Array Analysis
chemical_list: D014408:Biomarkers, Tumor; D053495:Osteopontin