A DNA repair mechanism may come at a cost -- cancer-causing mutations, according to a study published this week in Science.
DNA ligase repairs chromosomal damage
Image: Wikimedia commons, Tom
Ellenberger Washington
University School of Medicine
A supposedly accurate DNA repair mechanism employed by cells to fix double-strand breaks can surprisingly increase the nearby mutation rate by up to 1400 times, providing a possible explanation for the accumulation of tumor-causing mutations in cancerous tissues. Previously, "we saw that DNA breaks are present in precancerous legions," said molecular oncologist linkurl:Thanos Halazonetis;http://www.molbio.unige.ch/halazonetis/ of the University of Geneva, who did not participate in the research. "These breaks, based on this finding now, could perhaps explain [some of the] mutations in oncogenes that drive cancer progression." Cancer cells are the subject of unusually high numbers of mutations, but for many cancers, the cause of those mutations is unknown. Chromosomes are commonly rearranged in...
W.M. Hicks, et al., "Increased mutagenesis and unique mutation signature associated wit mitotic gene conversion," Science, 329:82-5, 2010.

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