Characteristics of tumor-infiltrating Treg cells

Foxp3-expressing regulatory T (Treg) cells play essential roles in immune homeostasis, but also contribute to establish a favorable environment for tumor growth by suppressing anti-tumor immune responses. It is thus necessary to specifically target tumor-infiltrating Treg cells to minimize effects on immune homeostasis in cancer immunotherapy. Here we show that tumor-infiltrating Treg cells have activation-associated, yet distinct transcriptomic and epigenetic landscape compared to effector Treg cells in secondary lymphoid organs and that down-regulation of TCF7 and LEF1 in tumor-infiltrating Treg cells is a key discriminative feature.