title: Protein profiling in pancreatic juice for detection of intraductal papillary mucinous neoplasm of the pancreas.
abstract: OBJECTIVE
  Malignant intraductal papillary mucinous neoplasm of the pancreas (IPMN) has a very poor prognosis, and there is no useful biomarker for an early diagnosis at present. A biomarker is expected to allow an early diagnosis of IPMNs and consequently lead to an improvement of the patients' prognosis. Recent advances in proteomic analysis are remarkable; therefore we explored novel biomarkers for IPMN using Surface-Enhanced Laser Desorption and Ionization (SELDI) Mass Spectrometry.
  
  
  METHODS
  We collected pancreatic juice samples from 33 patients with IPMNs, 54 patients with pancreatic ductal carcinoma, and 31 with chronic pancreatitis. We analyzed the pancreatic juice samples using a SELDI ProteinChip system (Ciphergen Biosystems, Fremont, CA).
  
  
  RESULTS
  We identified a 6240-Da peak whose expression in pancreatic juice from patients with IPMNs was significantly higher compared with that in other pancreatic diseases (P<0.01). This 6240-Da protein was partially purified and was identified as pancreatic secretory trypsin inhibitor (PSTI) by amino acid sequencing. The pancreatic juice PSTI levels, as measured by radioimmunoassay, were significantly higher in the IPMN group than in the other groups (P<0.001). When the diagnostic cutoff value of PSTI in pancreatic juice was set at 25000 ng/mL, the positive predictive value, negative predictive value, sensitivity, and specificity were respectively 89%, 83%, 48%, and 98%.
  
  
  CONCLUSIONS
  PSTI levels of pancreatic juice in patients with IPMN were significantly higher than those in patients with other pancreatic diseases. The PSTI level in pancreatic juice may be useful for the diagnosis of IPMN.
authors.affiliation: Department of Medicine and Clinical Oncology, Graduate School of Medicine, Chiba University 1-8-1 Inohana, Chuo-ku, Chiba 260-8670, Japan. chiba0500@yahoo.co.jp
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Shirai
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Sogawa
authors.forename: Taketo
authors.initials: T
authors.lastname: Yamaguchi
authors.forename: Kentaro
authors.initials: K
authors.lastname: Sudo
authors.forename: Akihiko
authors.initials: A
authors.lastname: Nakagawa
authors.forename: Yuji
authors.initials: Y
authors.lastname: Sakai
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ishihara
authors.forename: Masahiko
authors.initials: M
authors.lastname: Sunaga
authors.forename: Masahiko
authors.initials: M
authors.lastname: Nezu
authors.forename: Takeshi
authors.initials: T
authors.lastname: Tomonaga
authors.forename: Masaru
authors.initials: M
authors.lastname: Miyazaki
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Saisho
authors.forename: Fumio
authors.initials: F
authors.lastname: Nomura
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000737:chemistry / Q000175:diagnosis*; D000595:Amino Acid Sequence; D014408:Biomarkers, Tumor / Q000032:analysis*; D021441:Carcinoma, Pancreatic Ductal / Q000737:chemistry / Q000175:diagnosis*; D002291:Carcinoma, Papillary / Q000737:chemistry / Q000175:diagnosis*; D002352:Carrier Proteins / Q000032:analysis*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D010189:Pancreatic Juice / Q000737:chemistry*; D010190:Pancreatic Neoplasms / Q000737:chemistry / Q000175:diagnosis*; D040081:Protein Array Analysis; D014359:Trypsin Inhibitor, Kazal Pancreatic
chemical_list: D014408:Biomarkers, Tumor; D002352:Carrier Proteins; C486642:SPINK1 protein, human; D014359:Trypsin Inhibitor, Kazal Pancreatic