CTCL derive from skin-homing T cells and consist of mycosis fungoides (MF), Sézary syndrome (SS), primary cutaneous CD30-positive T cell lymphoproliferative disorders: lymphomatoid papulosis (LP) and anaplastic large cell lymphoma (ALCL), cutaneous γδ TCL (CGD-TCL), cutaneous CD8-positive aggressive epidermotropic cytotoxic TCL (CD8 + AECTCL), and cutaneous CD4-positive small/medium TCL (CSM-TCL). The gene discussed is TNFRSF8; the disease is mycosis fungoides.