Inclusion Criteria:

   - 1. Diagnosis of diffuse large B-cell lymphoma, CD20-positive, according to the World
   Health Organization Classification, stages II-IV or limited stage I disease that is
   bulky (more than 10 cm) or with International Prognostic Index (IPI) score > 1.

   - 2. Patients must not have had prior chemotherapy, radiotherapy or immunotherapy. A
   short course (< 2 weeks) of corticosteroids is allowed.

   - 3. Adequate paraffin-embedded tumor specimen must be available for gene expression
   analysis and immunohistochemistry prior to initiation of therapy. (If the specimen is
   deemed inadequate, the subject can be retroactively screen failed, as this does not
   change the treatment regimen).

   - 4. Baseline measurements and evaluation must be obtained within 4 weeks before first
   treatment.

   - 5. Age >18 years.

   - 6. Eastern Cooperative Oncology Group (ECOG) performance status 0-3.

   - 7. Adequate organ function:

      - White Blood Cells count (WBC) >2500/µL

      - Absolute Neutrophil Count (ANC) > 1000/µL (unless due to disease in marrow)

      - platelet count >100,000/µL (unless due to disease in marrow)

      - creatinine < 2.0 mg/dL,

      - bilirubin < 1.5 mg/dL (may be 1.5-3.0 mg/dl if due to liver involvement by
      lymphoma)

      - Serum Glutamic Oxaloacetic Transaminase (SGOT)/ Serum Glutamic Pyruvic
      Transaminase (SGPT) <3 x upper limit of normal.

   - 8. Female patients must not be pregnant or breast feeding.

   - 9. Women of childbearing potential and men must be strongly advised to use an accepted
   and effective method of contraception.

   - 10. Patients must have left ventricular ejection fraction of >45%.

   - 11. Provision of written informed consent.

Exclusion Criteria:

   - 1. Patients with a second malignancy other than basal cell carcinoma of the skin or in
   situ carcinoma of the cervix unless the tumor was treated with curative intent at
   least two years previously; and; the patient continue to be free of evidence of
   recurrence.

   - 2. Patients with HIV infection as these patients are managed on dedicated protocols.

   - 3. Patients with active central nervous system (CNS) lymphoma.