Wang et al. demonstrated that in malignant pleural effusion (MPE), H3K18la promotes forkhead box protein P3 (FOXP3) expression in peripheral blood mononuclear cells (PBMCs), simultaneously enhancing the immunosuppressive function of Tregs while inhibiting NKT cell‒mediated anti‒tumor responses (Wang ZH. Here, FOXP3 is linked to neoplasm.