Characterization of Circulating IL-7R Positive Cell Populations for Early Detection of Pancreatic Ductal Adenocarcinoma.

(1) Background: Pancreatic cancer is a high devastating disease with the lowest survival rate among all common cancers due to difficulties in early diagnosis. The purpose of this study was to identify and characterize the distinct subset of blood cell population elevated in peripheral blood mononuclear cells (PBMC) of pancreatic cancer to evaluate the potential markers for diagnosis of pancreatic cancer; (2) Methods: We analyzed differential gene expression in PBMC from normal individuals and pancreatic cancer patients utilizing transcriptome analysis. Flow cytometry analysis was applied to identify the discrete subset of interleukin-7 receptor (IL-7R) expressing cells in these cells. The expression of IL-7R during tumorigenesis was determined in syngeneic mouse model of pancreatic cancer in vivo; (3) Results: PBMC from pancreatic cancer patients expressed elevated IL-7R mRNA compared to healthy control individuals. IL-7R expressing cells rapidly appeared from the early stages of the onset of tumor formation in syngeneic pancreatic cancer mouse model in vivo. The discrete subset of IL-7R positive cells mainly consist of naive T, central memory T, and effector memory T cells; (4) Conclusions: Taken together, our present findings suggest that pancreatic cancer patients expressed higher level of IL-7R expression in PBMC that rapidly emerged from the onset of early pancreatic tumor formation in vivo than normal individuals. Thus, it can be used as a novel biological marker for early events of pancreatic cancer development.