Times Online (Link) - Mark Henderson (December 17, 2009)
The complete genetic codes of two human cancers have been mapped for the first time. The move could herald a medical revolution in which every tumour can be targeted with personalised therapy.
The exhaustive genetic maps, which catalogue every DNA mutation found in two patients’ tumours, will transform treatment of the disease. It has been described as the most significant milestone in cancer research in more than a decade.
Scientists predict that by about 2020 all cancer patients could have their tumours analysed to find the genetic defects that drive them. This information would then be used to select the treatments most likely to work.
Insights from the genomes will also lead to the development of powerful drugs to target DNA errors that cause cancer and highlight ways in which the disease can be prevented. Cancers would be diagnosed and treated according to their genetic profiles rather than their position in the body.
“The pace at which genomics is moving is probably the most exciting thing that’s gone on in cancer research in more than a decade,” said Professor Sir John Bell, President of the Academy of Medical Sciences. “These cancer genome projects are a major landmark, as significant as the sequencing of the human genome itself.”
The research was led by Professor Mike Stratton, of the Cancer Genome Project at the Wellcome Trust Sanger Institute near Cambridge. He said that the findings would transform the way we see cancer.
“These catalogues of mutations are telling us about how the cancer has developed, so they will inform us on prevention. They tell us about all the processes which are disrupted in cancer cells, which we can try to influence through our treatments. So this is a really fundamental moment in the history of cancer research. I can envisage a time a decade or more hence when these catalogues will become routine, and influential in selecting treatment for that individual. That’s what we’re expecting — every cancer patient will have one of these charts.”
Cancer is a disease of the genes. Environmental factors such as smoking, radiation or alcohol consumption inflict DNA damage that causes cells to grow out of control.
The new maps, which are published in the journal Nature, plot this genetic chaos in unprecedented detail for the tumours of two cancer patients. One had small-cell lung cancer; the second had malignant melanoma, the deadliest form of skin cancer.
Sir Mark Walport, director of the Wellcome Trust, which funded the research, said: “This is the first glimpse of the future of cancer medicine, not only in the laboratory, but eventually in the clinic. The findings from today will feed into knowledge, methods and practice in patient care.”
The catalogues are the first of thousands that are being created by the International Cancer Genome Consortium, a £600 million project to identify all the mutations that drive 50 common types of cancer.
The initiative will sequence tumours from 500 patients with each cancer type, including several forms of breast and liver cancer, and compare the results with the genetic code of healthy cells. It will reveal which DNA defects contribute to the onset and spread of cancer, and which are incidental.
Peter Campbell, of the Sanger Institute, said: “The knowledge we extract over the next few years will have major implications for treatment. By identifying all the cancer genes we will be able to develop new drugs that target the specific mutated genes and work out which patients will benefit from these novel treatments.”
Harpal Kumar, chief executive of Cancer Research UK, added: “The next step will be to find out which of these thousands of mutations are just collateral damage, and which actually drive these cancers. Only then can we begin to find ways to correct or prevent them. Never before has the potential of genomics to bring benefits to patients been so apparent.”
CASE STUDY
The prospect of genetically mapping individual cancers was given a cautious welcome today by Tom Haswell, 64 (Lucy Bannerman writes).
When the lung cancer patient was diagnosed with a tumour the size of an orange in his chest, doctors said he had three to six months to live.
That was 16 years ago. Mr Haswell, who now describes his quality of life as “totally acceptable”, said he hoped the new research will help speed up the process of finding the right treatment for the right patient.
“The idea of targeting treatment options to one particular kind of cancer would be brilliant,” he said. “I hope it will eliminate the approach many people face after diagnosis, which is, ‘let’s try this, and if that doesn’t work, let’s try another.’
In his own case, Mr Haswell had to wait three months to be advised of his treatment options. Eventually, having been informed there were no suitable chemotherapy drugs and that curative radiotherapy would not be practical, the retired father of two from Glasgow decided to take part in a drug trial, which helped shrink the tumour significantly.
“I was told I could take part in the clinical trial or die, basically.
“So, I particularly like the idea of knowing treatment would be personalised. That would be a great benefit to everyone.
“I would also be interested to know the differences in mutations, for example, between cancers in smokers and non-smokers. Maybe that will help us understand why people who have never smoked, also develop the disease.”
If shortcuts are found, that could also help prevent patients having to go through gruelling treatments unnecessarily, Mr Haswell added.
However, he said: “From the point of view of researchers, and clinicians, this must be the best news they have had all year. “But from a patient perspective, I treat every new about a breakthrough, or ‘wonder drug’ with caution. These things take years to develop, so it is not going to have any benefit for today’s lung cancer patient.”
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