In what has been hailed as a "big step" towards answering one of medical science's great questions, the findings of researchers at the Roslin Institute could lead to new treatments and even cures for illnesses which affect the immune system.
It was previously thought that a select group of "master" genes was responsible for controlling the growth of cells that can cause the conditions.
But the study discovered that there are actually hundreds of genes which interact with each other in a way that is much more complicated than previously thought.
MS, a disease in which the immune system mistakenly attacks and damages sheaths that protect nerve cells, can cause symptoms ranging from vague tingling to blindness and paralysis. It affects one in every 500 people in Scotland – the highest proportion in the world – and nearly 100,000 across the UK.
Professor David Hume, the director of the University of Edinburgh's Roslin Institute, said a whole new field of scientific research had been opened up, which would dramatically alter the way in which vaccines were used and drugs were tested.
MS charities last night welcomed the findings which, they said, highlighted Scotland's leading role in research into the illness, while cancer specialists described the breakthrough as "exciting".
Professor Hume said: "This research provides an incredible resource for the study of immunity and disease in humans and animals. This study has effectively shown us where the brakes are which could slow down or stop diseases like cancer and multiple sclerosis. We believe that this could lead to treatments and cures for many diseases of the immune system."
The scientists said they believed that variations in this network explained why people could develop diseases in different ways.
The team hopes that, by identifying weak spots in the gene structure, they will be able to stop the growth of tumours, enabling the growth of healthy cells.
They also hope the new research could lead to treatments for the likes of myeloid leukaemia and arthritis.
The researchers said the findings offered up previously hidden information about the immune system and could ultimately help doctors understand why some cancer patients responded to immunotherapies while others did not.
Professor Hume, who carried out the three-year study as part of a team of international researchers, focused on the immune system and examined the genes involved with white blood cells called macrophages.
When healthy, these cells cleanse the body of viruses and bacteria, but if they grow uncontrollably, they can turn against the body's own tissue to cause conditions such as MS, arthritis and emphysema.
It was previously thought that such cell-growth processes were managed by a select group of master, or regulator, genes that give instructions to many other genes.
However, the research makes clear that there are, in fact, hundreds of regulator genes which all interact with each other to control cell development and growth. Scientists say it helps to explain why people can develop the same disease in different ways, because of variations in different parts of their genetic networks.
By identifying the weak spots in these networks, it is hoped it will soon be possible to stop the growth of tumours, or enable the growth of healthy cells.
Prof Hume, recognised as an international authority in genome sciences, said last night the study was akin to discovering the function of every single part of a car, whereas before only eight or nine were known.
He added: "The traditional way we have carried out research in this area is to look at one gene at a time. We thought processes like cells growing or dying were controlled by a very small number of master genes, but in fact it's an entire environment that creates the changes, with around 20,000 different elements.
"It means we have a much better understanding of how tumours develop.
"There are literally thousands of different ways of developing a tumour, and every one is likely to be different. That represents a serious challenge for us, but it gives us hope that, depending on how the tumour arises, we can know what therapies will be useful."
He said: "We will be able to understand why different people have different responses to pathogens. If you infect a large number of people with influenza, only a few would get sick – we now know why, and how to prevent it from happening. It will make a significant difference to the way vaccines are used and the way drugs are tested, as we will be able to establish likely side-effects to therapies."
Dr Lesley Walker, director of cancer information at Cancer Research UK, said: "This exciting research reveals just how complex the development of our immune system is – areas of the genome that we thought were dormant may actually play an important role in guiding its evolution."
She added: "The studies may eventually help to explain why some people respond to immunotherapies and others don't."
A spokesman for the Multiple Sclerosis Society Scotland, the charity of which JK Rowling served until recently as patron, said: "Every day, researchers are learning more about the genetic make-up of MS, and anything that helps put the pieces of this complex puzzle together must be a good thing.
"This study also highlights the important role that research in Scotland is playing in developing our understanding of MS and other autoimmune conditions," the spokesman added.
Dr Mark Matfield, scientific adviser for the St Andrews-based Association for International Cancer Research, said: "This is a really powerful new study of how cells work. It shows us the mechanisms controlling how cells change are much more complicated than we thought. It may go some way to explain why it has been so difficult to understand these mechanisms.
"This study only looks at white blood cells, and we'll need to find out if this is generally true in other types of cells," he said. "However, this clearly takes us one big step closer to understanding the way cells grow and change – one of the great questions of medical science."
The discovery is regarded as an important breakthrough for the Roslin Institute, which formed a multi-million-pound partnership with the University of Edinburgh last year. Scientists intend to extend the project with funding from the Biotechnology and Biological Sciences Research Council to look at the way genes communicate to control immunity in livestock animals.
The study was conducted as part of the Functional Annotation of the Mammalian cDNA (FANTOM], a consortium comprising scientists at the Roslin Institute, the RIKEN Yokohama Institute in Japan, and researchers from the US, Canada, Australia, Switzerland, Norway, South Africa, Sweden, Denmark, Italy, Germany, and Singapore.
The main points of the discovery and what it means
1 Scientists probed the genes involved with white blood cells called macrophages, which measure just 21 micrometres in diameter. When healthy, the cells cleanse the human body of bacteria and viruses.
2 Sometimes the macrophages grow uncontrollably, turning against the body's own tissue. This can lead to the development of conditions such as multiple sclerosis, cancer, arthritis, and emphysema.
3 It was previously believed these processes were caused by a small number of master, or regulator, genes. However, the new research reveals there are hundreds of these types of genes, all interacting in tens of thousands of ways.
4 The findings will allow scientists to find out in greater detail how tumours develop. It is hoped they will be able to develop specific therapies depending on how the tumour has formed.
'You mourn for your future'
SUE Polson, 59, noticed she had a numb ankle after working in her garden 11 years ago. When the numbness began to spread up her leg, she visited her doctor who sent her to hospital.
Doctors at Edinburgh's Western General believed she had damaged her spine and carried out a series of tests. She was then sent home and told her problem had been a one-off. But eight months later, the symptoms returned and Mrs Polson was finally diagnosed with relapsing/remitting Multiple Sclerosis (MS). The condition sees a person's immune system attack the central nervous system, leading to physical disability.
"I had a catastrophic attack in 2000 and couldn't walk," she said. "I was in hospital for a long time and had to learn to stand and walk again. I found it very frustrating to give up my career. I was very angry at the time."
She added: "Mentally, it's a huge adjustment. It's the loss of your health and your future and there's a time of mourning because you know there's nothing you can do to stop it."
After that attack Mrs Polson, who now lives in Crossford near Dunfermline, was put on an immunosuppressant drug called Azathioprine which helped manage her condition, though her health continued to deteriorate.
"This new discovery looks fantastic and I look forward to seeing more details," she said. "I would like to be some years younger so I could benefit but I don't care as long as something is happening."
Poor lifestyle choices cause more cancer than genes
PEOPLE should stop believing cancer is just down to "bad luck" or their genes and look to their own lifestyle, an expert said yesterday.
An unhealthy diet and poor lifestyle – such as a lack of exercise and being overweight – causes three times as many cases of cancer as genetics, said Dr Rachel Thompson, science programme manager for the World Cancer Research Fund (WCRF).
Evidence suggests that only about 5-10 per cent of all cancers result from specifically inherited genes. Meanwhile, 39 per cent of the most common cancers could be prevented through following a good diet, exercising and keeping weight down.
Dr Thompson said: "It's important to dispel the myth that cancer is just down to genes. The evidence shows that an unhealthy diet and low activity levels cause three times more cancer cases than genes.
"If people do have a family history, then this is important information, but overall this inherited genetic predisposition is uncommon."
According to SCRF scientists, people who inherit these genes have a higher than average risk of cancer but won't certainly develop the disease.
SCOURGE AFFECTS THOUSANDS
MULTIPLE Sclerosis (MS) is the most common disabling neurological condition affecting adults. About 85,000 people in the UK and 10,500 people in Scotland have the condition.
Scotland is known as the MS capital of the world as it has more people with the condition per capita than anywhere else.
MS is the result of damage to myelin – a protective sheath surrounding nerve fibres of the central nervous system. It is split into two types, relapsing/remitting MS, where a person has flare-ups that can result in extreme levels of disability followed by periods of significant recovery, and progressive MS, which is a slower but permanent degeneration.
Diagnosis is 50 per cent more common in woman than men and the average age of diagnosis is the mid-thirties.
Symptoms of MS are varied and can include problems with balance, bladder and bowel, fatigue, memory and concentration difficulties, depression and emotional problems, vision problems, speech difficulties, tremors and swallowing problems.
THE CURSE OF CANCER
ABOUT 27,000 people are diagnosed with cancer in Scotland each year.
Breast, lung, bowel and prostate are the four most common cancers and make up more than half of all cases diagnosed.
More than one in three of us will get some form of cancer at some point in our lives.
One in four people dies from cancer.
Cancer has been the most common cause of death in women since 1969 and in men since 1995.
The main treatments for cancer are surgery, chemotherapy, radiotherapy, bone-marrow and stem-cell transplants, biological therapy, hormone therapy and gene therapy.
In Scotland, about half of women and 40 per cent of men survive for at least five years after diagnosis.