Researchers decode complete DNA of cancer patient
Published Friday, November 7, 2008 11:43AM EST
A group of U.S. scientists have mapped the genome of a woman who died of leukemia and identified 10 gene mutations they believe contributed to the cancer that killed her.
The woman, who was in her mid-50s, died two years after she was first diagnosed with acute myeloid leukemia -- a cancer that kills 8,800 Americans each year.
The scientists took samples of both healthy skin cells and tumour cells from the woman's body, and then sequenced the DNA of each of her samples.
Dr. Thomas Hudson, president and scientific director of the Ontario Institute for Cancer Research, is familiar with the research that was led by researchers at Washington University and published in the Nov. 6 issue of the journal Nature.
He spoke to Canada AM on Friday and said that these scientists zeroed in on "100,000 changes that are in the tumour but not in the normal DNA of that individual."
And from this very long list of "abnormalities," the scientists identified 10 key gene mutations they believed to be driving the cancer within the woman's body, he said.
The scientists found that each of the cancerous cell samples tended to have nine of 10 gene mutations that were not present in healthy cell samples.
Two of these 10 gene mutations, the scientists report in Nature, have previously been suspected of contributing to the progression of tumours.
The cellular function of the other eight mutations is not known, but the scientists saw them in nearly every tumour cell sample under study.
The scientists concluded that many more tumours -- perhaps hundreds or thousands -- would have to be studied in order to determine how important the 10 gene mutations are.
But the method they used to investigate the tumour is something many other scientists will take note of, as the study is believed to be the first to use genome sequencing in identifying cancer-initiating gene mutations.
Hudson said the research has pushed the envelope for cancer researchers.
"We've only been able to study genes by the tens, hundreds and so on," he told Canada AM on Friday. "This is the first one that we've sequenced an entire genome."
"This is like the Human Genome Project," he said. "That took ten years, hundreds of labs, almost $1 billion dollars. And now, five, six years later, we look at the first cancer genome for about one-millionth of that cost."