• 5/28/2007
  • London, England
  • Mark Henderson and Lewis Smith
  • The Times (www.timesonline.co.uk)

A revolution in cancer screening and treatment within 15 years is heralded today with the announcement of a leap in the ability to identify genes that cause the disease.

Researchers are confident that their findings will allow a screening programme, in which the inherited risk of developing cancer can be assessed for every patient, to be in place in an estimated 12-15 years.

Four common genes were identified and a fifth is on the verge of being pinpointed by researchers investigating the causes of breast cancer, almost doubling the number of known rogue genes.

One of the new genes, when found in a mutated form, increases the risk of developing the cancer by up to 60 per cent — giving a woman a one in six chance of the disease. Its most damaging variant is carried by one in six women, making it much more common than previously identified genes that contribute to breast cancer.

The success of a new “trawling technique” to assess 200,000 blocks of DNA simultaneously instead of one by one is expected to transform the search for treatments for all common cancers.

While the research concentrated on identifying genes linked to breast cancer, the same technique can equally well be used for other types of the disease and work has already started on applying it to prostate, bowel and lung cancer.

One scientist described the findings as the most important in breast cancer genetics since 1993 and 1995 when the first identification of genes that increase the risk of developing the cancer was made.

The research is the first success for a new approach to scanning large stretches of the human genome for cancer genes. Instead of focusing on one gene and trying to work out if it increased the likelihood of cancer developing, researchers were able to compare 200,000 blocks of DNA, or tags, of 800 women to narrow down the suspect genes.

Professor Bruce Ponder, of the University of Cambridge, led the study and said that the technique should speed up the rate of gene identification enormously for a range of cancers.

“Previously scientists have had to search for new cancer genes one at a time, but we have been able to search two thirds of the genome in one go,” he said. “Rather than fish for new genes one at a time with a rod and line, we have trawled the pool. This is not only a more efficient approach, it gets round the bias of previous studies in which scientists only examined genes they already knew something about.”

The discovery could help doctors to calculate a woman’s predisposition to develop breast cancer over a lifetime.

The genes identified in the latest research present a comparatively small added risk of cancer developing in any woman who has mutated versions of them.

However, they are much more common and while individually only increase the risk by a small proportion, the more mutated versions a woman has, the greater the chance of developing the disease.

In time, and if there are the resources within the NHS, researchers anticipate that patients could be tested for all the inherited genetic mutations and given a comprehensive risk assessment.

Only a fraction of the total number of genes with inherited mutations causing cancer have yet been identified but researchers are certain that they will find more as they carry out further studies and fine-tune their techniques.

The research was an international collaboration involving scientists from across Britain and the world and is published in several papers in the journals Nature and Nature Genetics. Harpal Kumar, chief executive of Cancer Research UK, said that this was “an outstanding discovery” that would “open doors across the globe.”

Independent cancer specialists welcomed the research. Professor Karol Sikora of Imperial College School of Medicine in London said: “This set of incredible papers points to the future.”