Landmark study reveals over 70 new genetic variants linked to cancer
In one of the largest cancer studies ever, a significant amount of new gene discoveries have been uncovered, almost doubling the number of known cancer genes that cause the three most common cancers of breast cancer, prostate cancer and ovarian cancer.
Researchers say that the study, conducted through the Collaborative Oncological Gene-Environment Study (COGS), will advance understanding of the biological causes of cancer. But they caution that they still do not know enough about breast, prostate and ovarian cancer to predict who will get them on the basis of genetics alone.
“People are already asking us, ‘Shouldn’t you genotype all people, to determine their individual risk for being diagnosed with these cancers?’”, says Per Hall, coordinator of the COGS. “But it’s too early,” he added
Hall and his team surveyed genetic markers in over 200,000 people who had already been studied in previous projects. By pooling these people into a 'mega-consortium', investigators increased their ability to detect common variants linked to cancer risk. As a result, they found 74 new genetic variants linked to the cancers. They also found that many of these variants were linked to more than one cancer.
Variations in the DNA sequence at 27 different positions (loci) in the genome have previously been found to be associated with breast cancer risk. In this study, all but four of these previously identified loci showed clear evidence of association with breast cancer in this study.
Moreover, the researchers found 41 new loci that were significantly associated with the risk of breast cancer, with each locus being associated with an increased risk of breast cancer. They estimate that these 41 associated loci explain about five percent of breast cancer in families – and that a larger number of loci could contribute to susceptibility in breast cancer, while suggesting 1,000 additional loci are involved in breast cancer susceptibility.
“This indicates common underlying functional mechanisms at some of these susceptibility loci, and could lead to the identification of common biomarkers and therapeutic targets for intervention across several disease sites,” says geneticist Simon Gayther of the University of Southern California in Los Angeles.
The study has the potential to lead to genetic profiling that may help to identify women who are susceptible or are otherwise at an increased risk of developing breast cancer, including women who are at an increased risk of developing ovarian cancer, not to mention men who are at an increased risk of prostate cancer.
The study was published March 27 in the journal, Nature. Researchers say their findings have the potential to help doctors determine which patients need testing for cancer more often and help identify more effective treatments based on a particular patient’s individual needs.
“By looking for people who carry most of these variations we will be able to identify those who are at the greatest risk of getting these cancers and then targeting screening tests to these individuals,” said Douglas Easton of Britain’s University of Cambridge, who led some of the studies.
“We now have 76 common genetic variants which are associated with breast cancer risk,” Easton said.
SOURCE: Nature, March 27, 2013 (doi:10.1038/nature.2013.12675)