Genetic errors identified in 12 major cancer types

By analysing DNA in more than 3,000 tumours, scientists led by Li Ding, PhD, at The Genome Institute have identified 127 repeatedly mutated genes that likely drive the growth of a range of cancers in the body. The discovery sets the stage for devising new diagnostic tools and more personalised cancer treatments aimed at the unique genetic changes found in individual tumours.
The research shows that some of the same genes commonly mutated in certain cancers also occur in seemingly unrelated tumours. For example, a gene mutated in 25 percent of leukaemia cases in the study also was found in tumours of the breast, rectum, head and neck, kidney, lung, ovary and uterus.
Based on the findings, the researchers envision that a single test that surveys errors in a swath of cancer genes eventually could become part of the standard diagnostic workup for most cancers. Results of such testing could guide treatment decisions for patients based on the unique genetic signatures of their tumours.
New insights into cancer are possible because of advances in genome sequencing that enable scientists to analyse the DNA of cancer cells on a scale that is much faster and less expensive today than even a few years ago. While earlier genome studies typically have focused on individual tumour types, the current research is one of the first to look across many different types of cancer.
‘This is just the beginning,’ said senior author Li Ding, PhD, of The Genome Institute at Washington University. ‘Many oncologists and scientists have wondered whether it’s possible to come up with a complete list of cancer genes responsible for all human cancers. I think we’re getting closer to that.’
The new research analysed the genes from 3,281 tumours – a collection of cancers of the breast, uterus, head and neck, colon and rectum, bladder, kidney, ovary, lung, brain and blood. In addition to finding common links among genes in different cancers, the researchers also identified a number of mutations exclusive to particular cancer types.
Looking at a large number of tumours across many different cancers gives the researchers the statistical power they need to identify significantly mutated genes. These genetic errors occur frequently in some cancers and rarely in others but are nevertheless thought to be important to cancer growth. The research was conducted as part of The Cancer Genome Atlas Pan-Cancer effort, funded by the National Cancer Institute and the National Human Genome Research Institute, both at the National Institutes of Health (NIH).
While the average number of mutated genes in tumours varied among the cancer types, most tumours had only two to six mutations in genes that drive cancer. This may be one reason why cancer is so common, the researchers said. ‘While cells in the body continually accumulate new mutations over the years, it only takes a few mutations in key driver genes to transform a healthy cell into a cancer cell,’ noted Ding. Washington University School of Medicine at St. Louis