Relationship between liver metastasis and epithelial-mesenchymal transition phenotype of circulating tumor cells in patients with pancreatic cancer

Objective: To study the relationship between epithelial-mesenchymal transition (EMT) phenotype of circulating tumor cells (CTCs) and liver metastasis of pancreatic cancer.Methods: The patients who were found without liver metastasis by preoperative imaging examination but confirmed with pancreatic cancer by postoperative pathological diagnosis were recruited in this study from January 2010 to December 2013 in Department of General Surgery, Changzheng Hospital, Second Military Medical University. All patients were followed up for 1 year after surgical operation, then divided into liver metastasis group and non-liver metastasis group according to whether the patient had liver metastasis or not during the follow-up. In each group, 50 patients were randomly selected. The peripheral blood samples from all patients were collected before surgery, and at the same time, the peripheral blood samples from 10 healthy volunteers were collected as the control. Then the CTCs were enriched and isolated from peripheral blood samples using immunomagnetic method, and identified by immunofluorescence method with carbamoyl-phosphate synthetase 1 (CPS1) antibody. The expressions of EMT markers Snail and Vimentin in blood samples were detected by immunofluorescence method. The relationships between these EMT markers and liver metastasis of pancreatic cancer were analyzed by univariate and multivariate analyses.Results: CPS1, Snail and Vimentin were not expressed in blood samples from 10 healthy volunteers. In peripheral blood samples from 50 pancreatic cancer patients with liver metastasis, the positive expression rates of Snail and Vimentin were 82% (41) and 72% (36), respectively; while in non-liver metastasis group, the positive expression rates of Snail and Vimentin were 20% (10) and 12% (6), respectively. The positive expression rates of Snail and Vimentin in liver metastasis group were higher than those in non-liver metastasis group (χ2 = 38.455, P 37 kU/L, tumor diameter ≥ 4 cm, pancreatic head tumors, vascular invasion, and positive expressions of Snail and Vimentin were correlated with liver metastasis of pancreatic cancer (all P 37 kU/L (β = 3.411, P < 0.01) and positive expressions of Snail (β = 2.882, P < 0.01) and Vimentin (β = 3.361, P < 0.01) were independent risk factors for liver metastasis of pancreatic cancer.Conclusion: CTCs-EMT phenotype markers Snail and Vimentin in peripheral blood may be closely related to liver metastasis of pancreatic cancer. DOI:10.3781/j.issn.1000-7431.2015.33.221