TP53 and B-cell chronic lymphocytic leukemia: The disruption of TP53 has been found in 4% to 8% of newly diagnosed CLL, while, as the disease progresses, the frequency of TP53 abnormalities rises, reaching a prevalence of 10–12% at the time of first treatment requirement, ~40% in patients refractory to fludarabine, and 50–60% in those who develop RS [69].