Abstract
To establish prognostic biomarkers and to identify potential novel therapeutic targets, we performed integrative immunomonitoring of blood and tumor in patients with resectable pancreatic cancer. Flow cytometry (FC) was employed for phenotyping immune cells, multiplex bead assays for plasma cytokine and chemokine determination, and RNA-Seq for the analysis of gene expression in the tumor. Nineteen pancreatic cancer patients were stratified into those with longer or shorter than median recurrence-free survival after surgery (median, 426 days). There were no significant differences between the two groups for clinical parameters including age, sex, surgical procedure, stage, or postoperative adjuvant therapy. However, we found that the percentages of NK cells as assessed by FC in peripheral blood mononuclear cells were higher in patients with late recurrence (P = .037). RNA-Seq data indicated no differences in the amount of immune cells or stromal cells between the two groups, although NK cells in the tumor did tend to be higher in patients with late recurrence (P = .058). Type I and II IFN signatures were enriched in late-recurring tumors (FDR q-value <0.001), while genes related to KRAS signaling and the epithelial mesenchymal transition (EMT) were enriched in early recurrence. We conclude that tumor-intrinsic properties of metastasis and recurrence influence prognosis, whereas NK cells that might contribute to prevent metastasis are associated with longer recurrence-free survival. Therefore, enhancement of NK cell activity and inhibition of the EMT and KRAS signaling might represent appropriate therapeutic targets following surgical resection of pancreatic cancer.