Mantle cell lymphoma (MCL) is a distinct subtype of B-cell non-Hodgkin's lymphoma (NHL). Although the cancer begins in the mantle zone, the lymphoma cells can accumulate, enter the lymphatic system and the blood, and spread to other lymph nodes or tissues such as the spleen, liver, bone marrow, and gastrointestinal tract. Patients with MCL are typically older adults, predominately male, and present with advanced-stage disease. Approximately 65,980 people will be diagnosed with NHL in 2009, and MCL accounts for 5% to 8% of all NHL cases. Although MCL often responds to initial treatment, it is associated with a high relapse rate. In the relapsed and refractory states, partial responses to treatment and a short duration of benefit are common. MCL patients generally have a poor prognosis with a median overall survival of 3 to 4 years from diagnosis. There is no consensus for the treatment of patients with MCL, and it is considered an incurable disease.