title: Soluble gC1qR in Blood and Body Fluids: Examination in a Pancreatic Cancer Patient Cohort.
abstract: BACKGROUND
  gC1qR is a multifunctional cellular protein that has been linked to inflammation and cancer. gC1qR is highly upregulated in adenocarcinomas as compared to normal tissue counterparts, and soluble gC1qR (sgC1qR) has been detectedin vitroin the pericellular milieu of proliferating malignant cells.
  
  
  OBJECTIVE
  The present study explored the tissue expression of gC1qR in pancreatic cancer by immunohistochemistry, and the presence of sgC1qRin vivo, by examining blood and malignant effusions from patients with metastatic pancreatic adenocarcinoma.
  
  
  METHODS
  Tissue expression of gC1qR by pancreatic adenocarcinoma was visualized by immunohistochemistry. SgC1qR was quantified in serum from healthy volunteers (n=20) and pancreatic cancer patients (n=34), as well as in malignant pleural (n=23) and peritoneal effusions (n=27), using a newly developed, sensitive immunocapture sandwich ELISA.
  
  
  RESULTS
  Overexpression of gC1qR was confirmed in pancreatic adenocarcinoma compared to nonmalignant pancreatic tissue. Moreover, increased serum levels of sgC1qR (0.29 ± 0.22 ng/ml) were noted in patients with metastatic pancreatic cancer compared to healthy controls (0.15 ± 0.10 ng/ml) (mean ± S.D.) (p=0.035). In 11 of 16 patients for whom sequential samples were available, serum sgC1qR levels rose with disease progression, and paralleled changes in tumor biomarkers, CEA and CA19.9. In addition to blood, sgC1qR was detected in malignant pleural (0.55 ± 0.47 ng/ml) and peritoneal effusions (0.57 ± 0.38 ng/ml).
  
  
  CONCLUSIONS
  This study provides the first evidence for the presence of sgC1qRin vivo. The ability to detect sgC1qR in blood and body fluids will enable further studies to elucidate its pathophysiology in malignancy.
authors.affiliation: Department of Laboratory Medicine, Memorial Sloan Kettering Cancer Center and Department of Laboratory Medicine and Pathology, Weill Cornell Medical Center, NY, NY, USA.
authors.forename: Ellinor Ib
authors.initials: EI
authors.lastname: Peerschke
authors.affiliation: Hycult Biotech, R&D Department, Uden, The Netherlands.
authors.forename: Ricardo Jmge
authors.initials: RJ
authors.lastname: Brandwijk
authors.affiliation: Department of Pathology, Mount Sinai School of Medicine, NY, NY, USA.
authors.forename: Francine R
authors.initials: FR
authors.lastname: Dembitzer
authors.affiliation: Department of Pathology, Mount Sinai School of Medicine, NY, NY, USA.
authors.forename: Yayoi
authors.initials: Y
authors.lastname: Kinoshita
authors.affiliation: Department of Medicine, Stony Brook University, Stony Brook NY, USA.
authors.forename: Berhane
authors.initials: B
authors.lastname: Ghebrehiwet
keywords: Blood; Complement; ELISA; Pancreatic cancer; Peritoneal fluid; gC1qR