CCR4 and synovial sarcoma: SS is associated with the neoplastic evolution of central memory T cells, expressing C-C chemokine receptor type (CCR) 7, CCR4, L-selectin, and CD27, while MF is linked to skin-resident effector memory T cells, lacking CCR7/L-selectin and CD27 expression, but featuring high levels of CCR4 and cutaneous lymphocyte antigen (CLA) [6,7].