CCR4 and adult T-cell leukemia/lymphoma: ATLL has a poor prognosis and survival which is influenced by key prognostic factors such as poor performance status, elevated LDH levels, a minimum of four involved lesions, hypercalcemia, minimum age of 40 years, thrombocytopenia, eosinophilia, bone marrow involvement, high interleukin-5 serum levels, C–C chemokine receptor 4 (CCR4) expression, lung resistance-related protein, p53 mutation and p16 deletion [18].