Moreover, GOF mutations in CCR7 have been also reported in 11% of ATLL cases [103], and in patients with lymphoid organ infiltration, ATLL cells were further shown to upregulate CCR7 whose expression in CD4+CCR4+ ATLL cells is associated with aggressive ATLL while its absence is associated with progressive indolent ATLL [80,104]. This evidence concerns the gene CCR4 and adult T-cell leukemia/lymphoma.