Such effort has led to the CLL International Prognostic Index (CLL-IPI), which helps predict patient outcome [e.g., 5-year overall survival (OS)] based on five well-established prognostic markers: the IGHV and TP53 mutational status of CLL cells, the patient’s age and clinical stage, and β2-microglobulin (β2m) serum levels at diagnosis [3,4]. Here, B2M is linked to B-cell chronic lymphocytic leukemia.