Standardized peptidome profiling of human serum for the detection of pancreatic cancer.

OBJECTIVE

To establish new biomarkers for accurate diagnosis of pancreatic cancer (PC) using a standardized serum peptidome profiling and compare the results with those from the tumor marker, CA 19-9.

METHODS

Serum samples from 102 patients (55 with chronic pancreatitis and 47 with PC) and 56 healthy controls were collected and analyzed following a protocol that was rigorously designed to prevent preanalytical variation. Serum peptides were extracted using immobilized copper ion chromatography on a robotic platform. Mass spectra were acquired by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry on an Autoflex II spectrometer (Bruker Daltonics, Bremen, Germany). Statistical analysis was performed using the Clinprotools 2.2 software (Bruker Daltonics) and the SPSS 15.0 software (SPSS Inc, Chicago, Ill).

RESULTS

Standardized peptidome profiling showed a median coefficient of variation of 11.6% calculated using all the extracted peptides and negligible influence of sex and age on peptidome profiles. The diagnostic sensitivity was 89.9%, and the diagnostic specificity was 92.7%, using 2 serum features and CA 19-9 serum concentration. Healthy controls were differentiated from patients with PC and chronic pancreatitis, with the use of 3 features of the peptidome (diagnostic sensitivity, 98.2%; diagnostic specificity, 97.1%).

CONCLUSIONS

Standardized serum peptidome profiling could be a useful tool to improve biochemical diagnosis of PC in combination with the classic tumor marker, CA 19-9.