ATM and B-cell chronic lymphocytic leukemia: Mutations in ataxia-telangiectasia mutated (ATM, the gene mutated in A-T) have also been detected in sporadic lymphoid tumors, such as T-cell prolymphocytic leukemia [3], [4], [5], B-cell chronic lymphocytic leukemia [6], [7], [8] and mantle cell lymphoma [9].