TGFB1 and cancer: Only one of these inhibitors (GC1008, a monoclonal pan-TGFβ neutralizing antibody otherwise known as fresolimumab) has been evaluated for its impact on immune cell populations in cancer patients, and it was shown to have no impact on Treg frequency or the expression of activation markers on CD4+ T cells, CD8+ T cells or NK cells in patients with malignant pleural mesothelioma (MPM).