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The identification of a gene that significantly influences the risk of breast cancer is reported in Nature Genetics. The findings indicate that a mutation of the gene may account for up to 1% of breast cancers in women, and 9% of breast cancers in men. BRCA1 and BRCA2 are widely considered to be THE breast cancer genes. But mutations in these genes account for only a small fraction of breast cancers. To search for additional genetic risk factors, a consortium of three groups screened individuals from 718 families with a history of breast cancer and without mutations in either the BRCA1 or BRCA2 genes.
They discovered that a mutation in a well-characterized gene, called CHEK2, confers a twofold increase in risk of breast cancer in women and a tenfold increase in risk of breast cancer in men. However, the mutation does not increase the risk of breast cancer in people carrying mutations in the BRCA1 or BRCA2 genes, which is consistent with previous studies showing that BRCA1 and CHEK2 participate in the same biochemical pathway. (It also suggests that CHEK2 and BRCA2 are also in the same pathway.) Disruption of this pathway is thought to increase susceptibility to breast cancer. The CHEK2 protein is an enzyme involved in cell proliferation. It is activated when cellular DNA is damaged, leading to a pause in cell division, so that the damage may be repaired. The CHEK2 mutation was previously shown to eliminate enzyme activity. Thus, the æbrakeÆ that is CHEK2 is broken, leaving the cell to contend with replicating damaged DNAùa scenario that leads to genome instability, and potentially, cancer. The discovery that a CHEK2 variant causes susceptibility to breast cancer provides hope that, despite the slow progress in identifying genes involved in breast cancer, other large studies may yield up additional genes. Author contacts: Dr Nazneen Rahman or Dr Michael Stratton
Institute of Cancer Research
Surrey, UK
Tel +44 20 8722 4026
E-mail: nazneen@icr.ac.uk or mikes@icr.ac.uk Dr Douglas Easton
Strangeways Research Laboratories
Cambridge, UK
Tel +44 1223 740 161
E-mail: douglas@srl.cam.ac.uk, Dr Hanne Meijers-Heijboer or Dr Mieke Schutte,
Erasmus Medical Center
Rotterdam, The Netherlands
Tel +31 104 366 590
E-mail: meijers@kgen.fgg.eur.nl Published Online. (C) Nature Genetics press release.
Message posted by: Trevor M. D'Souza
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