TGFB1 and neoplasm: Treg cells are characterized by high expression of CD25 and the transcription factor FOXP3.129 They inhibit T cell activation by producing inhibitory cytokines, including IL-10, IL-35, and TGF-β, or by expressing CTLA4 that competes with CD28 to combine with CD80/86.130–132 In mouse lung cancer models, Treg cells increased in TLSs around blood vessels and are associated with TLSs in tumor stroma, leading to a poor prognosis for patients.