IL-4 and IL-13, cytokines abundantly produced in later stages of MF and in SS, can enhance CCR8 expression on malignant T cells and may stimulate keratinocytes and myeloid cells to secrete CCL1, thereby creating a positive feedback loop for tumor cell recruitment and survival in the skin (39, 42, 43). The gene discussed is CCR8; the disease is synovial sarcoma.