ATM and cancer: ATM is considered a tumor suppressor as its deletion in mice results in tumors, patients with mutations in ATM in the human disorder Ataxia telangiectasia have increased cancer risks, and several hematological cancers have been reported to express defective ATM (Cremona and Behrens, 2013; Shiloh and Ziv, 2013; Stracker et al., 2013).