Fig. 1.

A systems biology overview of research on diagnostic biomarkers for early detection of pancreatic ductal adenocarcinoma (PDAC). Sampling sources including blood, cyst fluid, pancreatic juice, bile, and urine can be used for biomarker analysis. Systems biology integrates genomics, transcriptomics, proteomics, and metabonomics data into an integrated molecular network. Bioinformatics tools are applied to the integrated data to discover diagnostic biomarkers. Once the biomarkers are verified in clinical trials, they may eventually be applied in clinical practice.