11q22–23 deletion characterizes a CLL subtype with extensive nodal involvement and inferior prognosis.78 The minimal region of deletion involves the ataxia-teleangiectasia mutated (ATM) gene, with concurrent mutation of the remaining ATM allele occurring in 30–40% of 11q- cases and causing extreme telomere shortening79 and dismal prognosis.80 Because ATM is a very large gene, mutational studies were not performed in clinical trials and papers included in this review refer to patients with 11q-. The gene discussed is ATM; the disease is B-cell chronic lymphocytic leukemia.