MUC1 and familial pancreatic carcinoma: However, not all studies have shown a clear association between circulating microvesicle-TF activity and VTE occurrence in pancreatic cancer.56 In addition, the intensity of TF expression by adenocarcinoma cells does not necessarily correlate with plasma microvesicle-TF activity.48 Moreover, a study involving three pancreatic cancer patients showed that 50% of TF-positive microvesicles were MUC1-negative,60 indicating a source of TF-positive microvesicles separate from tumour cells.