Despite these advances, CLL remains incurable with standard therapies; patients inevitably relapse, become increasingly refractory to treatment, and often acquire high-risk chromosomal abnormalities such as del(11q22) and del(17p13), which correspond to loss of the ataxia telangiectasia mutated (ATM) and p53 tumor suppressor genes, respectively. The gene discussed is ATM; the disease is B-cell chronic lymphocytic leukemia.