A common variant on chromosome 8 that predisposes to prostate cancer also confers risk of colorectal cancer, according to three studies to be published online in Nature Genetics. Although a few relatively rare mutations have been identified that are associated with colorectal cancer, this is the first evidence for a common genetic risk factor. Colorectal cancer is one of the most commonly diagnosed forms of cancer.
In the first study, Richard Houlston, Ian Tomlinson and colleagues carried out a genome-wide association study for colorectal cancer and identified the most strongly associated variant on chromosome 8 as the same variant that had previously been associated with risk of prostate cancer. In the second study, Thomas Hudson, Malcolm Dunlop and colleagues screened a smaller number of variants across the genome but identified the same one on chromosome 8 as highly associated with colorectal cancer. Finally, Christopher Haiman and colleagues noted that the region on chromosome 8 that was shown to be associated with prostate cancer is also known to be amplified in individuals with colorectal cancer. Given this background they directly assessed the relevant variants in individuals with colorectal cancer and found them to be significantly more frequent than in cancer-free individuals. Haiman and colleagues also note that five other variants in this region that had been associated with prostate cancer were not associated with colorectal cancer, suggesting that the mechanism by which variants in the region contribute to cancer risk may differ depending on the type of cancer.
Authors paper 
Richard Houlston (Institute of Cancer Research, Sutton, UK)
Ian Tomlinson (Bart's and the London Medical School, London, UK)
Authors paper 
Thomas Hudson (The Ontario Institute for Cancer Research, Toronto, Ontario, Canada)
Malcolm Dunlop (University of Edinburgh, UK)
Author paper 
Christopher Haiman (University of Southern California, Los Angeles, CA, USA)
Abstracts available online:
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