Adult T-cell leukemia/lymphoma (ATLL) is a rare form of cancer found mostly among people from the Caribbean islands, Western Africa, Brazil, Iran, and Japan. Most cases of this disease in the United States occur along the East Coast due to emigration from the Caribbean islands. There is currently no standard treatment for ATLL. Research shows that patients who go into first time remission (respond completely or partially to treatment) and have a bone marrow transplant have the best outcomes. Traditional chemotherapy treatments have generally not worked well in patients with ATLL. Additionally, not all patients will be eligible for a bone marrow transplant.