Biologic and clinical significance of molecular profiling in Chronic Lymphocytic Leukemia.

CLL is extremely heterogeneous in its clinical course, with some patients living decades with no need for treatment whilst others have a rapidly aggressive clinical course. A major focus of research has been to try to identify those biological factors that influence this heterogeneity. The goal of therapy has been to maintain the best quality of life and treat only when patients become symptomatic from their disease. For the majority of patients this means following a "watch and wait" approach to determine the rate of progression of the disease and assess for development of symptoms. Any alteration to this approach will require identification of criteria that define patients sufficiently "high-risk" that they gain benefit by introduction of early therapy. The use of molecular profiling to suggest particular therapies is currently appropriate only in defining the treatment of the minority of patients with 17p deletions or p53 mutations and in all other circumstances remains a clinical trial question.