CA19-9-Positive Extracellular Vesicle Is a Risk Factor for Cancer-Associated Thrombosis in Pancreatic Cancer

Cancer-associated venous thromboembolism (VTE) is a frequent complication associated with high mortality in patients with cancer, particularly pancreatic cancer. While biological factors such as coagulation factors released from cancer cells may underlie the mechanisms of cancer-associated VTE, the detailed mechanisms have not been determined. Here, we aimed to determine whether extracellular vesicles carrying a glycan sialyl-Lewis^a, known as carbohydrate antigen 19-9 (CA19-9), which is a clinically used serum tumor marker and selectin ligand, are a significant cause of cancer-associated VTE.

Risk factors for cancer-associated VTE were determined using clinical data. EVs derived from CA19-9-deficient or overexpressing pancreatic cancer cells were characterized. The protein levels of coagulation factors on the surface of the EVs were quantified using our newly developed sensitive method.

Higher CA19-9 levels in the sera of patients were significantly associated with the occurrence of VTE. Using CA19-9-negative or overexpressing pancreatic cancer cells, we found that EVs derived from these cells interacted with E-selectin of endothelial cells in a CA19-9-dependent manner in cell-based assays and in vitro blood vessel models. EVs derived from cancer cells have higher tissue factor levels on their surfaces, and increased tissue factor activity is induced locally, where CA19-9-positive EVs bind to activated endothelial cells.

These results suggest that the binding between CA19-9-positive EVs released from cancer cells and endothelial cell E-selectin explains the increased frequency of VTE in patients with pancreatic cancer.