 To evaluate the efficacy and safety of lenalidomide, rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone R2-CHOP chemotherapy versus placebo, rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone placebo-R-CHOP chemotherapy in patients who have previously untreated ABC type DLBCL. 