title: Detection of pancreatic cancer with normal carbohydrate antigen 19-9 using protein chip technology.
abstract: OBJECTIVE
  To develop a method to differentiate pancreatic cancer patients from healthy or benign individuals when carbohydrate antigen (CA) 19-9 is normal.
  
  
  METHODS
  Forty-one serum samples from patients with pancreatic lesions and blood samples from 20 healthy individuals were collected at the first stage of the experiment according to the enrolment criteria. General characteristics and some clinical features were carefully compared to ensure that the results were reasonable. All the blood samples were analyzed by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS) combined with CM10 chips and a related bioinformatics analysis program to generate diagnostic models with different proteins. Forty-seven consecutive samples were tested at the next stage to verify the veracity and efficiency of the models.
  
  
  RESULTS
  The sex, age, and serum CA19-9 levels among the three groups (malignant, benign, and healthy) were statistically matched (P values were 0.957, 0.145, and 0.382, respectively). Two patterns were generated. Pattern 1 with four proteins theoretically had a specificity and sensitivity of 100% in distinguishing pancreatic cancer from healthy individuals, while it was 86.7% and 86.4%, respectively, in the subsequent practical verification. The positive predictive value (PPV) of the model was 86.4%. One of the four proteins was expressed highly in pancreatic cancer while the other three were expressed weakly. Pattern 2 consisted of six proteins that showed a specificity of 70.0% and sensitivity of 77.3% for differentiating malignancy from benign tumors. Its PPV reached 85.0%. Only one of these six proteins showed high expression in the malignant group.
  
  
  CONCLUSIONS
  SELDI-TOF-MS may facilitate diagnosis or differential diagnosis of pancreatic cancer when CA19-9 is normal. Pattern 1 may serve as a useful screening tool.
authors.affiliation: Xiao-Li Jin, Bin Xu, Department of Surgery, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310016, Zhejiang Province, China.
authors.forename: Xiao-Li
authors.initials: XL
authors.lastname: Jin
authors.affiliation: Xiao-Li Jin, Bin Xu, Department of Surgery, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310016, Zhejiang Province, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Xu
authors.affiliation: Xiao-Li Jin, Bin Xu, Department of Surgery, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310016, Zhejiang Province, China.
authors.forename: Yu-Lian
authors.initials: YL
authors.lastname: Wu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018395:CA-19-9 Antigen / Q000097:blood*; D016022:Case-Control Studies; D019295:Computational Biology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000097:blood*; D009367:Neoplasm Staging; D010190:Pancreatic Neoplasms / Q000097:blood* / Q000145:classification / Q000473:pathology; D011237:Predictive Value of Tests; D040081:Protein Array Analysis; D015203:Reproducibility of Results; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D018395:CA-19-9 Antigen; D009363:Neoplasm Proteins
keywords: Carbohydrate antigen 19-9; Diagnosis; Pancreatic cancer; Screening; Surface-enhanced laser desorption/ionization time-of-flight mass spectrometry