It is reported that FOXP3 plays two key roles: (1) the tumor suppressor in prostate, ovarian, and breast cancers via activating tumor-suppressor genes and inhibiting several oncogenes; (2) a biomarker related with poor prognosis in melanoma, non-small cell lung cancer, urinary bladder cancer, and esophageal cancer (126). The gene discussed is FOXP3; the disease is neoplasm.