Patients with mantle cell lymphoma 18 years and older who have not been treated previously with chemotherapy may participate in this study. Candidates will be screened for eligibility with a medical history and physical examination. Other tests that may be required include blood and urine tests; lung function studies; imaging tests such as magnetic resonance imaging, computed tomography and X-rays; and biopsy (surgical removal of a small tissue sample) of tumor, bone marrow, or other tissue.