Advances in molecular biology diagnostic and treatment of B-cell malignancies: indolent B-cell lymphoma.

Follicular lymphoma (FL) represents 60% of indolent lymphoma (15–30% of all malignant lymphomas) and is thus one the most frequent lymphoma subtypes, with a rapidly increasing incidence in Western countries [1]. The clinical course is characterized by a slowly progressive disease but continuous relapse pattern, with a median overall survival of 5–10 years. The vast majority of patients presents with advanced stages III or IV (Ann Arbor classification) at initial diagnosis; accordingly, conventional chemotherapy is only palliative [2]. Therefore, a watch and wait strategy is generally recommended in patients with low tumor burden and no clinical symptoms, because various randomized trials have demonstrated that earlier initiation of cytoreductive therapy is not superior to observation with regard to overall survival [3–5]. When FL becomes symptomatic chemotherapy induces remissions in the vast majority of patients, but does not prevent recurrent relapses and finally refractory disease. In addition, the survival of these patients has remained essentially unchanged despite intensive clinical research and exploration of different therapeutic strategies over the last 30 years [2]. Recently, a new prognostic score (Follicular Lymphoma International Prognostic Index, FLIPI) of five risk factors including number of nodal areas, lactate dehydrogenase, stage, age, and hemoglobin level has been proposed to predict the outcome of individual patients with newly diagnosed FL, which will allow more risk-adapted therapeutic strategies in future trials [6]. However, so far, validating data from prospective studies are limited [7].