Mantle cell lymphoma (MCL) accounts for approximately 6% of non-Hodgkin's lymphomas. Patients usually present with advanced disease, with a tendency for extranodal involvement. MCL is an aggressive lymphoma with moderate chemosensitivity, but it remains one of the most difficult therapeutic challenges. Complete response rates to chemotherapy range from 20% to 40%, with median survivals of 2 1/2 to 3 years. Anthracycline-containing regimens do not prolong survival compared with nonanthracycline regimens. Single-agent rituximab (Rituxan) has produced response rates of about 30%, and when combined with an anthracycline-containing regimen, response rates increase to above 90%; however, an impact on survival has not yet been demonstrated. More intensive regimens such as hyperCVAD (hyperfractionated cyclophosphamide [Cytoxan, Neosar], vincristine, doxorubicin [Adriamycin], dexamethasone, methotrexate, cytarabine) with either stem cell transplant or rituximab have been associated with promising results.