152. Endothelial Progenitor Cell Decrease After Resection of Pancreatic Adenocarcinoma

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Introduction: Angiogenic factors released by cancers stimulate endothelial progenitor cell (EPC) migration from the bone marrow through the peripheral blood to the tumor bed to contribute to neovascularization. This study was designed to measure EPCs in the peripheral blood of patients with pancreatic cancer and determine if EPC levels are elevated in patients with pancreatic cancer when compared to healthy controls or patients with benign pancreatic lesions and to determine if EPC levels decline after pancreatic cancer resection. Consistent with the idea that pancreatic cancer is a source for EPC-mobilizing angiogenic factors, we hypothesized that the EPC level in patients with pancreatic cancer are higher than in controls and that EPC levels decline after resection of pancreatic cancer. Methods: Venous blood was collected from patients before and at time points after surgery. Peripheral blood mononuclear cells (PBMCs) were isolated using density gradient centrifugation, FcR-blocked, and stained with phycoerythrin (PE)-labeled anti-VEGFR2, allophycocyanin (APC)-labeled anti-CD133, and fluorescein isothiocyanate (FITC)-labeled anti-CD34 or with the appropriate isotype controls. Samples were evaluated in duplicate (200,000 cells per sample) via flow cytometry and analyzed using WinList software. EPCs were identified as low side scatter (SSC) CD34+CD133+VEGFR2+. These cells were counted and expressed as a percent of live cells obtained. Statistical analysis was conducted using the independent t test. Results: The average preoperative EPC level was 6-fold higher in patients with pancreatic cancer (n = 9) than in healthy controls (n = 4) (0.0063% vs 0.0010%, p = 0.00065). The average preoperative EPC level was 4-fold higher in patients with pancreatic cancer than in patients with benign pancreatic lesions (n = 2) (0.0063% vs 0.0016%, p = 0.016). There was no difference between the preoperative EPC level in healthy patients when compared to patients with benign pancreatic lesions (p = 0.54). Seven of nine patients with pancreatic adenocarcinoma (4 female, 5 male), had resectable tumors. Following resection, EPCs decreased an average of 85.4%. This decline was exhibited within 7 weeks post-operatively (Figure 1).