For this reason, there has been a great deal of effort placed on attempting to define disease characteristics that predispose patients to a poorer prognosis with R-CHOP therapy. Molecular and gene expression profiling of tumors and a variety of clinical prognostic indices have been used to identify patients at higher risk of failing R-CHOP immunochemotherapy. While this work has identified subgroups of patients who do not respond well to R-CHOP, to date these efforts have not resulted in substantial gains in response to front-line therapy.