The loss of chromosome 11’s long arm (del 11q) and chromosome 17’s short arm (del 17p) are the two most high-risk groups of CLL that show the minimal overall survival (OS) and treatment-free interval (TFI), owing to the loss of the DNA damage-repair gene Ataxia telangiectasia, mutated (ATM) in del11q, and the tumor-suppressor gene TP53 in del 17p cases, respectively. This evidence concerns the gene ATM and B-cell chronic lymphocytic leukemia.