Kevin Coombes, PhD, Ohio State University, Columbus, OH, discusses identifying biological subsets of chronic lymphocytic leukemia (CLL) patients that are likely to respond to fludarabine, cyclophosphamide, rituximab (FCR) treatment. Dr Coombes elaborates on the statistical techniques and models used to predict which groups would respond best to treatment. This interview took place at the 18th International Workshop on Chronic Lymphocytic Leukemia (iwCLL) Biennial Meeting, held in Edinburgh, UK.