APP and neoplasm: The attenuation in Treg population from TIL, splenocytes, and DLN following oAd/APP+DC treatment was likely due to high intratumoral expression level of IL-12 (Figures 3A, 6B), as localized overexpression of IL-12 in tumor has been reported to reverse the immunosuppression by inducing apoptosis of Treg cells (66).