TP53 and B-cell chronic lymphocytic leukemia: The international prognostic index for chronic lymphocytic leukemia (CLL-IPI) combines five independent prognostic factors (TP53 status, IGVH mutational status, serum beta2-microglobulin, clinical stage according to Rai/Binet, and age) identifying four risk groups with significantly different 5-year overall survival (OS), from 93% (low risk) to 23% (very high risk) [11].