Epitherapy and immune checkpoint blockade: using epigenetic reinvigoration of exhausted and dysfunctional T cells to reimburse immunotherapy response.

Background: Cancer cells subvert natural immunosuppression by upregulating the expression of checkpoint proteins and their ligands. For example, tumor cells expressing programmed death-ligand 1 (PD-L1) induce immune cell tolerance to cancers, thereby facilitating tumor progression. The recent clinical success of immunotherapy, particularly checkpoint blockade, represents a significant advance in cancer therapy.