TNFSF10 and neoplasm: In this study, we had two specific goals: 1) investigate TRAIL function in an inducible, cell type–specific manner by generating Tnfsf10L/L mice on C57BL/6, BALB/c, and NOD backgrounds, as studies thus far have only used blocking Abs or constitutive Tnfsf10 knockout mice, and 2) assess if Tregs require and/or are dependent on TRAIL as a mechanism of suppression within the tumor or autoimmune microenvironment by use of Tnfsf10L/LFoxp3Cre mice.