Cell-extrinsic biomarkers for chronic lymphocytic leukemia (CLL) have a number of advantages. Here, Andreas Agathangelidis, PhD, of the Center for Research and Technology Hellas, Thermi, Greece, discusses cell-extrinsic biomarkers in CLL and what their role is in the management of the disease. Dr Agathangelidis highlights the importance of testing for immunoglobulin gene somatic hypermutation status in both routine practice and clinical trials. This interview took place at the European Research Initiative on CLL (ERIC) International Meeting 2018, held in Barcelona, Spain.