Detail of a diseased human lung. Photo: Getty Images

Detail of a diseased human lung. Photo: Getty Images

The genetic code of two of the most deadly cancers has been cracked by scientists in a world first that opens up a whole new era in the treatment for the disease.

All the mutations that turn healthy cells cancerous in both lung and skin tumours have been identified in what researchers described as a “transforming moment” in the search for preventions, treatments and cures for both terminal illnesses.

Such a detailed picture of the fundamental causes of the disease will lead to earlier detection, new breeds of drugs and better understanding of what causes the disease, they claim.



Eventually, a simple blood test will lead to accurate “made-to-measure” treatments that can identify, attack and kill the causes of each patient’s own individual cancer, they claim.

Professor Mike Stratton, of the Wellcome Trust Sanger Institute, a world-leading research centre in Cambridge in England, who carried out the studies, said: “What you are seeing today is going to transform the way that we see cancer.

“This is a really fundamental moment in the history of cancer research.”

All cancers are caused by damage or mutations to the DNA of formerly healthy cells.

This damage causes them to grow into abnormal lumps or tumours and spread around the body disrupting its normal processes and eventually — if unchecked — causing death.

In lung cancer, the damage is almost entirely caused by smoking; and in skin cancer or malignant melanoma by ultra-violent sunlight.

The studies used powerful new DNA sequencing technologies to decode completely the genome of both tumour tissue and normal tissue from a lung cancer and a malignant melanoma patient.

They then compared and contrasted the two to discover the differences and see what damage had occurred to cause the disease.

The lung cancer genome, which kills 34,500 people a year, contained more than 23,000 mutations; while the melanoma, which kills 2,000 people a year, contained more than 33,000.

Most of these mutations are known as “passengers” and cause damage but not cancer. However, a small number are called “drivers” and these lead to the disease.

By sequencing more cancer patients over the next few years, the researchers hope to distil down the mix until they have a handful of targets to hit with different treatments.

Technology

While the whole process for the studies took more than a year and cost around £80,000 (€90,000), the technology is moving so fast that it will soon take just weeks and cost less than £8,000 (€9,000).

It is eventually believed that a simple blood test will mean every patient will be given their own cancer chart so their treatment can be tailor made.

“The first time that people began to think there was something about genetic material that contributed to cancer was about 100 years ago and they looked down the microscope at the nucleus (centre of cells) and saw it was abnormal,” said Prof Stratton.

“100 years later, today, we are seeing every single mutation in a cancer. We have never seen cancer revealed in this form before and these catalogues of mutations are telling us about how the cancer has developed so they will inform us on prevention.”

Already the lung cancer genome is yielding information. As the average victim has smoked 18,000 packets of cigarettes, the researchers have concluded that a mutation is caused roughly every 15 cigarettes.

Prof Peter Campbell, who led the lung cancer team, said: “These mutations are a bit like Russian roulette. Most of the time you will hit an empty chamber and cause a passenger mutation.

“But every now and again you will hit a bullet and cause a tumour.” (© Daily Telegraph, London)

- Richard Alleyne in London

Irish Independent