For the first time, researchers have decoded all the genes of a person with cancer and found a set of mutations that may have caused the disease or aided its progression.
Using cells donated by a woman in her 50s who died of leukemia, the scientists sequenced all the DNA from her cancer cells and compared it with the DNA from her healthy skin cells. Then, they zeroed in on 10 mutations that occurred only in the cancer cells, apparently spurring abnormal growth, preventing the cells from suppressing that growth and enabling them to fight off chemotherapy.
The findings will not help patients immediately, but researchers say they could lead to new therapies and will almost certainly help doctors make better choices among existing treatments, based on a more detailed genetic picture of each patient's cancer. Though the research involved leukemia, the same techniques can also be used to study other cancers.
"This is the first of many of these whole cancer genomes to be sequenced," said Richard Wilson, director of the Genome Sequencing Center at Washington University in St. Louis and the senior author of the study. "They'll give us a whole bunch of clues about what's going on in the DNA when cancer starts to bloom."
The mutations — genetic mistakes — found in this research were not inborn, but developed later in life, like most mutations that cause cancer. Only 5 percent to 10 percent of all cancers are thought to be hereditary.
The new research, by looking at the entire genome — all the DNA — and aiming to find all the mutations involved in a particular cancer, differs markedly from earlier studies, which have searched fewer genes. The project, which took months and cost $1-million, was made possible by recent advances in technology that have made it easier and cheaper to analyze DNA snippets. The study is being published today in the journal Nature.
Wilson said he hoped that in five to 20 years, decoding a patient's cancer genome would consist of dropping a spot of blood onto a chip that slides into a desktop computer and getting back a report that suggests which drugs will work best.