A serum-induced transcriptome and serum cytokine signature obtained at diagnosis correlates with the development of early pancreatic ductal adenocarcinoma metastasis

Immune indicators of PDAC progression were obtained from peripheral blood and analyzed in the context of each other by calculating a serum-induced transcriptome index and a serum cytokine index. Significant correlation of the transcriptome index with the inflammatory transcriptome index suggest that inflammtion has a role in PDAC progression. The segregation of metastatic progressed and not progressed patients when the inflammatory transcriptome index was analyzed in the context of the serum cytokine index suggest that the serum cytokine index may be a systemic biomarker of PDAC progression . Our data illustrates both the transcriptome and cytokine indices have promise as biomarkers of cancer immunity. For the transcriptome analysis, baseline (at diagnosis and before treatment) serum from patients with radiographic evidence of PDAC metastasis (i.e. progressed) and serum from patients without PDAC progression was incubated over peripheral blood mononuclear cells (PBMC) obtained from a normal donor. PBMC cRNA was hybridized to the GeneChip Human Genome U133 plus 2.0 array. Image data were analyzed with Affymetrix Expression Console 1.1.2 software and normalized using Partek Genomics Suite 6.5 to determine signal log intensities/ratios. The statistical significance of differential gene expression and false discovery rates (FDR) was determined through using RankProd Package in Bioconductor (www.bioconductor.org). Hierarchical clustering was conducted with Genesis.