Cancer risk and the ATM gene: a continuing debate.
Deficiencies in the ability of cells to sense and repair damage in individuals with rare genetic instability syndromes increase the risk of developing cancer. Ataxia-telangiectasia (A-T), such a condition, is associated with a high incidence of leukemia and lymphoma that develop in childhood. Although A-T is an autosomal recessive disorder, some penetrance appears in individuals with one mutated ATM gene (A-T carriers), namely, an increased risk of developing breast cancer. The gene mutated in A-T, designated ATM, is homologous to several DNA damage recognition and cell cycle checkpoint control genes from other organisms. Recent studies suggest that ATM is activated primarily in response to double-strand breaks, the major cytotoxic lesion caused by ionizing radiation, and can directly bind to and phosphorylate c-Abl, p53, and replication protein A (RPA). Analysis of ATM mutations in patients with A-T or with sporadic non-A-T cancers has suggested the existence of two classes of ATM mutation: null mutations leading to A-T and dominant negative missense mutations predisposing to cancer in the heterozygous state. Studies with A-T mouse models have helped determine the basis of lymphoid tumorigenesis in A-T and have shown that ATM plays a critical role in maintaining genetic stability by ensuring high-fidelity execution of chromosomal events. Thus, ATM appears to act as a caretaker of the genome.
Khanna
K K
KK
The Queensland Institute of Medical Research, Brisbane, Australia. kumkumK@qimr.edu.au
D001260:Ataxia Telangiectasia / Q000235:genetics; D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D005544:Forecasting; D006801:Humans; D008954:Models, Biological; D009154:Mutation; D009369:Neoplasms / Q000235:genetics*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics*; D012306:Risk; D025521:Tumor Suppressor Proteins
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D025521:Tumor Suppressor Proteins; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; C576325:Atm protein, mouse; D017346:Protein Serine-Threonine Kinases