TF and glioblastoma: For example, GBM lesions reportedly express higher levels of TF mRNA than lower-grade astrocytomas.104–107 This may in some cases be paralleled by the upregulation of TF antigen in situ, and by the release of TF-containing extracellular vesicles into the circulation108 (unpublished observations); however, the consistency and magnitude of these events still remain controversial.109,110