CCR4 and adult T-cell leukemia/lymphoma: The review was intended to cover the functional association of CCR4 with various T subsets and also to introduce the exciting success and subsequent approval of Mogamulizumab, a humanized and glyco-engineered monoclonal anti-CCR4, in the treatment of refractory/relapsed adult T-cell leukemia/lymphoma (ATLL) in Japan.