TGFB1 and neoplasm: In addition, TGF-β and other immunosuppressive molecules produced by tumor cells may recruit and activate immune cells including Tregs [85], MDSCs [86], CD11b+Ly6G+ neutrophils [87], and indoleamine 2,3-dioxygenase 1 (IDO1)-expressing DCs [88] that further suppress NK cell activity.