Science Weekly Podcast: Mammalian extinctions and malarial resistance

Posted by on August 23, 2011 Comments Off

In Science Weekly Alok Jha meets Dr Kate Jones from the Institute of Zoology to discuss the battle to stave off mammalian extinctions.

Camila Ruz talks to journalist and film maker Nisha Ligon about her recent trip to Thailand, where she is investigating malarial resistance and the growing fear among the medical and scientific communities that counterfeit drugs are accelerating the development of resistance to anti-malaria drugs.

Guardian science correspondent Ian Sample joins Alok and Kate to discuss some of this week's top science news stories including proof that coral reef disease is linked to human waste and why reefs are facing extinction, the consequences of alien contact and why a little exercise goes a long way to extend your life expectancy.

Subscribe for free via iTunes to ensure every episode gets delivered. (Here is the non-iTunes URL feed).

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We're always here when you need us. Listen back through our archive.

Alok JhaIan SampleJason PhippsCamila Ruz

Mapping the body: the temple

Posted by on August 23, 2011 Comments Off

It's the thinnest part of the skull, and also an area prone to skin cancer, making it a fascinating part of the body for surgeons

Sometimes, the significance a body part holds in one's clinical life changes over time. The first time I thought about the temple was during a head-and-neck tutorial, well over a decade ago. One of a small group of medical students, each clasping a human skull in our hands, I turned my own this way and that, trying intently to arrive at the correct answer to the question our anatomy demonstrator had just put to us – which part of the bony skull is the thinnest?

The word he was looking for was the pterion. Roughly corresponding to what we all know as the temple, this place – which takes its name from the Greek pteron, meaning wing (think of Hermes with wings attached to this part of his head) – is the junction of four separate skull bones, the frontal, parietal, temporal and sphenoid. Sometimes referred to in neurosurgical circles as "God's little joke", the bony pterion is not just a hazard zone because it is so thin, but also on account of a big artery, the middle meningeal, which runs immediately beneath it.

A direct blow to the pterion, or even an indirect blow to another part of the skull, may cause a fracture to this weak area, with an associated rupture of the underlying vessel. This can lead to something called an epidural haematoma, where blood builds up between the outer covering of the brain and the skull, with consequent pressure on the brain itself. Such an injury requires emergency surgery known as a craniotomy – where a hole is put in the skull, to let the blood out and so release cerebral pressure.

But this dramatic lesson is a far cry from my current temple-associated practice. Skin cancers often arise in this area, because of a person's lifetime exposure to the sun, and it is often not possible simply to sew up the hole in the skin after cutting a cancer out, since doing so can easily distort the contour of the eye. At such times, I opt for a Wolfe graft. After excising the cancer, I measure out a circle of equal size in the skin above the collar-bone (where the skin is similar) and remove it. I attach the graft to the patient's temple with tiny silk sutures. A nice pink Wolfe graft brings joy to the heart and heals with excellent cosmetic effect in just a few weeks.

Health & wellbeingMedical researchguardian.co.uk

Human guinea pigs lend their courage to a golden era of cancer research

Posted by on August 22, 2011 Comments Off

Cancer sufferers test drugs fresh from the laboratory in the hope of saving their own life and advancing knowledge of the disease

David Cox is a human guinea pig. He is also a man with a cancer for whom there are no more conventional options and who reasonably believes that, at 56, it is too early to call it a day. So Cox is only too happy to be one of the first people to try out a new drug, fresh from the laboratory. It could come with a load of unpleasant and unexpected side-effects. But it just might save his life.

Cox was diagnosed with mesothelioma three years ago – the result of working as an engineer in a boiler room full of asbestos, he believes. It's a cancer that doesn't usually have a good outcome. Like many people with advanced cancers, he has been on one trial after another. The last was a phase 2 – the trial of a drug that has been shown to be safe and have some effect in some people already. It seemed to work for six months, he said, and then it stopped.

"I went for the results of some scans on the Tuesday," he said. "They told me the results and the options I had. Within three days they'd got me on this trial." This is a phase 1 trial – a drug that has never been tested in humans before.

Cox didn't think twice about it. "I had nothing to lose," he said. When he was warned about possible side-effects, he remarked that the side-effects of not trying another drug were death. "You can't get much worse than that," he told his doctor.

Both his trials were run by the Royal Marsden, the world-renowned cancer hospital. The first was at its Chelsea site in west London. The latest is taking place at the other site in Sutton, south London, where the Marsden's cancer doctors work in close collaboration with scientists at the cutting edge of drug discovery and genomics in the adjoining building belonging to the Institute of Cancer Research.

When Harpal Kumar, chief executive of Cancer Research UK talks of a "golden era" of cancer research, these are some of the scientists and clinicians who are making it happen.

The Marsden uniquely has a drug development unit integrated into the hospital, allowing patients who have run out of options on conventional drugs to join trials where they can get the latest experimental medicines. Where those drugs were once aimed at a single cancer – breast or prostate or lung – these days they are targeted at particular mutations in the cancer. The old drugs worked in only up to a third of patients because each cancer is different. The new drugs aim to have a higher success rate – in a much smaller group of patients tested for the particular mutation.

Sarah Stapleton who runs the unit, said: "The patients have exhausted standard therapies and they are offered the option of a voluntary trial of targeted therapy."

For the volunteers with advanced cancers, these experimental drugs are their last chance, but Stapleton and the doctors have to be careful what they say to them. "We have to be very honest about what we're offering to our patients here. There are lots of ethical considerations for a patient entering a trial. These drugs are at a very early stage. They might not help and there is a fairly low chance of helping and they could cause them more problems in terms of side-effects than they are experiencing at the moment.

"The key is explaining it is not a miracle drug. Sometimes that is what people can expect, but it is not what we have got."

A trial will last two or three years. Patients have to stay in hospital usually for the first month – though they go home at weekends. "It is a huge time commitment because they have to come every week. We are going to take some time that they may not get back," said Stapleton. But many are philosophical and altruistic. They join the trial in the hope that it may help others, even if not themselves.

The exciting times are when they see particularly good and sometimes even dramatic results. It happened with a drug to prevent cancer returning in women with the BRCA genes that predispose them to breast and ovarian cancer. "We saw very good response rates from that," said Stapleton.

If Kumar from Cancer Research is right, the unit could be seeing more and more good outcomes. The Marsden is involved in the tumour testing trial that is about to start – supplying patients and also one of the three labs that will design and interpret panels of genetic tests. Somehow, they have to do it within a tight budget – the plan is to find a relatively cheap and feasible way to offer these molecular diagnostic tests across the whole of the NHS.

Dr David Gonzalez de Castro, head of the Marsden's molecular diagnostics laboratory, said the first two years, involving 9,000 tumour samples from patients in seven hospitals, was a bid to find out whether it was possible. "The question is can the NHS provide molecular diagnosis for all cancer types routinely and can this be linked not only to patient outcome but also research?" he said.

Each genetic test for lung, colorectal or breast cancer costs around £150 to £200. Cancer Research's plan is to carry out a panel of five or six tests for each cancer type for maybe £300. Gonzalez de Castro shakes his head in a sort of wonder. "It's a challenge," he says with a laugh. If all goes well, after two years the tests will begin to be offered in a further 10 to 20 centres. Then before long, the testing will be available throughout the NHS. The government is behind the scheme – it committed to developing and funding a national testing structure in the last cancer plan in January.

The testing is essential even now to find out whether, for instance, a woman with breast cancer is HER2 positive and needs Herceptin or a man with bowel cancer has a K-RAS gene mutation and should be given another cancer drug called cetuximab. Yet, according to a recent study by the Royal College of Pathologists, not everybody who needs a test is getting one.

But the new trial has a second and equally important and exciting purpose beyond securing equal access to tumour testing. All the patients who join will be asked if their results can be stored, along with details of their treatment and the outcomes. Cancer Research will be working with the cancer registries who already collect anonymised data on patients, said James Peach, its director of stratified medicine who is in charge of the project.

It is exciting, says Peach, because researchers will be able to find out what works, not just in terms of drugs but also surgery and radiotherapy, for people with cancers caused by specific genetic mutations. It opens the way to much better, more accurate treatment. "We will find out which drugs we should not be using and discover combinations we did not know about," he said. There will also be significant benefits in surgery and radiotherapy, because scientists may discover which sorts of tumours are likely to be more aggressive than others.

CancerMedical researchCancerHealthSarah Boseleyguardian.co.uk

Did Mozart die of a lack of sunlight?

Posted by on August 22, 2011 Comments Off

There are endless theories about why Mozart died at the age of 35, but the reality could be quite simple

Wolfgang Amadeus Mozart has died a hundred deaths, more or less. Here's a new one: darkness.

Doctors over the years have resurrected the story of Mozart's death again and again, each time proposing some alternative horrifying medical reason why the 18th century's most celebrated and prolific composer keeled over at age 35. A new monograph suggests that Mozart died from too little sunlight.

The researchers give us a simple theory. When exposed to sunlight, people's skin naturally produces vitamin D. Mozart, toward the end of his life, was nearly as nocturnal as a vampire, so his skin probably produced very little vitamin D. (The man failed to take any vitamin D supplements to counteract that deficiency. But that wasn't Mozart's fault. Only much later, in the 1920s, did scientists identify a clear link between vitamin D, sunlight, and good health. Vitamin D supplements did not go on sale in Salzburg and Vienna, Mozart's home towns, until many years after that.)

Stefan Pilz (who, if he plays his cards right, will hereafter be known as "Vitamin" Pilz) and William B Grant published their report, called Vitamin D Deficiency Contributed to Mozart's Death, in a journal called Medical Problems of Performing Artists. Pilz is a physician/researcher at the Medical University of Graz, Austria. Grant is a California physicist whose background is in optical and laser remote sensing of the atmosphere, and atmospheric sciences.

Pilz and Grant explain: "Mozart did much of his composing at night, so would have slept during much of the day. At the latitude of Vienna, 48º N, it is impossible to make vitamin D from solar ultraviolet-B irradiance for about six months of the year. Mozart died on 5 December, 1791, two to three months into the vitamin D winter."

But they acknowledge the existence of competing medical theories. They do not bother mentioning the possibility, depicted in Peter Shaffer's 1969 play Amadeus, that a rival composer did him in. Other academic studies do examine the evidence for poisoning; most conclude that that evidence is lame.

Rival doctors and historians have presented arguments, in medical and other academic journals, that Mozart perished from acute rheumatic fever, bacterial endocarditis, streptococcal septicemia, tuberculosis, cardiovascular disease, brain hemorrhage, hypertensive encephalopathy, congestive heart failure, uremia secondary to chronic kidney disease, pyelonephritis, congenital urinary tract anomaly with obstructive uropathy, bronchopneumonia, hemorrhagic shock, post-streptococcal Henoch-Schönlein purpura, polyarthritis, trichinellosis, amyloidosis, and quite a few other unpleasantnesses.

Other studies have tried to tease out biomedical causes for some of Mozart's eccentric behaviour. Two of the more abstruse are by Benjamin Simkin. In 1999 he wrote about a concept called "pediatric autoimmune neuropsychiatric disorder associated with streptococcal infection" (Pandas). The study is called Was Pandas Associated with Mozart's Personality Idiosyncrasies? It expanded on Simkin's curse-filled 1992 monograph, in the British Medical Journal, called Mozart's Scatological Disorder.

(Thanks to Jim Cowdery for bringing this to my attention.)

• Marc Abrahams is editor of the bimonthly Annals of Improbable Research and organiser of the Ig Nobel prize

NutritionMedical researchResearchHigher educationMarc Abrahamsguardian.co.uk

Radio review: Cancer Trials – Behind the Scenes at the Christie

Posted by on August 21, 2011 Comments Off

This look at people taking part in drug trials was, understandably, a sobering experience

Broadcast over two Sundays, Cancer Trials – Behind the Scenes at the Christie (5 Live) was a sobering listen, as you might expect. Presenter Jeff Bird followed the stories of those taking part in drug trials when no other options remain. It movingly captured moments when hope appears to drain away, and then flicker back into view, but only through sometimes entirely untested drugs. One woman Bird spoke to was the first person in the world to take her medication.

You could hear in patients' voices how these drugs throw out the possibility of a lifeline, however tangled and slippery. Dale, fighting lung cancer, was on his second trial and sounding remarkably chipper. "It's more fishing and time to enjoy myself," he said of doing the trial. After five weeks, though, a scan brought bad news. "It's showing specks appearing elsewhere on my lung," he said, his voice flatter, the hope momentarily knocked out of it. We left him about to start a third trial; I listened to that with fingers crossed.

It was particularly sad hearing mothers trying to keep things together ("I was pleased it was me and not another member of my family") and not being able to countenance the trial not working. As a mother to young twins put it, "Me not being here isn't an option."

RadioMedical researchHealthHealthcare industryElisabeth Mahoneyguardian.co.uk

Chronic fatigue syndrome researchers face death threats from militants

Posted by on August 20, 2011 Comments Off

Scientists are subjected to a campaign of abuse and violence

The full extent of the campaign of intimidation, attacks and death threats made against scientists by activists who claim researchers are suppressing the real cause of chronic fatigue syndrome is revealed today by the Observer. According to the police, the militants are now considered to be as dangerous and uncompromising as animal rights extremists.

One researcher told the Observer that a woman protester who had turned up at one of his lectures was found to be carrying a knife. Another scientist had to abandon a collaboration with American doctors after being told she risked being shot, while another was punched in the street. All said they had received death threats and vitriolic abuse.

In addition, activists – who attack scientists who suggest the syndrome has any kind of psychological association – have bombarded researchers with freedom of information requests, made rounds of complaints to university ethical committees about scientists' behaviour, and sent letters falsely alleging that individual scientists are in the pay of drug and insurance companies.

"I published a study which these extremists did not like and was subjected to a staggering volley of horrible abuse," said Professor Myra McClure, head of infectious diseases at Imperial College London. "One man wrote he was having pleasure imagining that he was watching me drown. He sent that every day for months."

Chronic fatigue syndrome – also known as myalgic encephalomyelitis (ME) – is common and debilitating. A recent BMJ (formerly the British Medical Journal) feature suggested that as many as one in 250 people in the UK suffers from it. Patients are sometimes unable to move and become bedridden, occasionally having to be fed through a tube. For more than 20 years, scientists have struggled to find the cause, with some pointing to physiological reasons, in particular viral infections, while others have argued that psychological problems are involved.

It is the latter group that has become the subject of extremists' attacks. The antagonists hate any suggestion of a psychological component and insist it is due to external causes, in particular viruses. In the case of McClure, her "crime" was to publish a paper indicating that early studies linking the syndrome to the virus XMRV were wrong and the result of laboratory contamination. So furious was the reaction that she had to withdraw from a US collaboration because she was warned she might be shot.

A similar hate campaign was triggered by a study published in the Lancet earlier this year. It suggested that a psychological technique known as cognitive behavioural therapy could help some sufferers. This produced furious attacks on the scientists involved, including Michael Sharpe, professor of psychological medicine at Oxford University. He had already been stalked by one woman who was subsequently found to be carrying a knife at one of his lectures.

"The tragedy is that this tiny group of activists are driving young scientists from working in the field," said Sharpe. "In the end, these campaigns are only going to harm patients."

This point was backed by Fiona Fox, director of the Science Media Centre. "Using threats and intimidation to prevent scientists pursuing specific avenues of research or speaking out is damaging not just science. It harms society," she said.

None of the scientists contacted by the Observer believed chronic fatigue syndrome was purely psychological. All thought external causes were involved. "There is an element that is heritable," said Dr Esther Crawley, a consultant paediatrician at Bristol University. "We also know that in children it is often triggered by a virus infection, while in adults it is associated with social deprivation. Stress and adversity is involved. To call this yuppie flu – as people have done – is a complete misnomer."

Crawley has spent years trying to unravel the causes, but her refusal to accept that the condition is a result only of organic external factors has resulted in her being deluged with hate mail from extremists. "You evil bastards … time is running out for you so you have [sic] better start denouncing your flawed inhumane therapy and pray to God for forgiveness," said one.

"To those who are responsible for preventing us sick ME sufferers from getting the help we need ... you will all pay," stated another. "It is depressing to receive emails like that, but I make sure that it does not get me down," said Crawley. "I do check packages that are sent to my office, however."

Many of the extremists' claims are bizarre, said Professor Simon Wessely, of the Institute of Psychiatry at King's College London. "They say I am in league with pharmaceutical companies in order to suppress data that shows a link between viruses and the syndrome. But why on earth would drug companies do that? If they could link the condition to a virus they would be well on the way to developing lucrative treatments and vaccines. It is crazy."

Wessely has installed speed dial phones and panic buttons at the police's request and has his mail X-rayed. He gave up his research on chronic fatigue syndrome several years ago, though he still treats patients. "I have moved my research interests to studies of Gulf war syndrome and other conditions linked to war zones," he said. "That has taken me to Iraq and Afghanistan where quite frankly I feel a lot safer – and I don't mean that as a joke."

Chronic fatigue syndromeMedical researchHealthRobin McKieguardian.co.uk

Medical researchers get £800m boost

Posted by on August 18, 2011 Comments Off

Record government funding will be spent over five years on research into diseases such as cancer, diabetes and Alzheimer's

Some of the best known hospitals and universities will get a record £800m boost for medical research as well as creating the new generation of patient treatments, the government has announced.

The cash, the largest single cash injection into early stage research in the NHS, will be spent over five years benefiting patients with diseases such as cancer, diabetes and heart disease.

The research will be carried out through NHS and university partnerships managed by the National Institute for Health Research (NIHR).

The biggest winners are Imperial College and Imperial NHS Trust – which will get £112m for its pioneering work in genetics, bioengineering and cancer. Moorfield's hospital and its partner University College London will get £26m including cash for their revolutionary techniques to grow transparent eye tissue in the laboratory.

Less well-known hospitals also won important awards – South London and Maudsley NHS Foundation Trust and King's College London will get £48m and money for software packages which can pinpoint early stage Alzheimer's disease.

The award, paid out once every five years, is at least £170m more than the last cash payments made under the last Labour government and £25m more than the chancellor announced in his March budget. Many see this as a victory for the new chief medical officer Sally Davies and it also underlines the significance of the life sciences and pharmaceutical industries to Britain.

Announcing the money David Cameron said: "A strong competitive science and research base is a crucial part of securing sustainable economic growth and creating jobs of the future, and we have some of the best scientists and facilities in the world. This investment will help ensure we continue to be at the cutting edge."

The health secretary Andrew Lansley describes the projects being sponsored as "translational research", which he explains is "developing exciting new science into tangible, effective treatments that can be used across the NHS".

Recently, more than 100 of the world's most senior chemists, including six Nobel laureates, wrote to Mr Cameron to warn of the impact of proposed cuts in funding for scientific research essential to industries ranging from biotechnology to agriculture. Budget cuts in this area are expected to amount to up to 15% in real terms over the next few years.

Colin Blakemore, professor of neuroscience at the University of Oxford which will share £95m with the local Radcliffe NHS trust, said it was good to see "the research budget of the NHS has been protected during the current period of upheaval and financial constraint".

However he warned that with the government pushing for more private sector companies to supply health services that there would have to be provisions to make sure that any commercial providers who win NHS contracts are also obliged to support research: "The NHS has a very different culture of commitment from what we sometimes see from private companies".

Medical researchNHSHealthCancerDiabetesAlzheimer'sHigher educationRandeep Rameshguardian.co.uk

Letters: Antidepressant use must be reviewed

Posted by on August 17, 2011 Comments Off

Your article about depression touches on the important point that those who have suffered abuse in childhood respond less well to drug and psychological treatments (Abused children twice as prone to depression, 15 August). This underscores the importance of people experiencing mental health problems getting regular reviews of their treatment so that GPs can monitor if it is working.

Platform 51 research last month showed that one in four women currently on antidepressants have waited a year or more for a review, and one in four women have been on them for 10 years or more. These statistics suggest that support structures are breaking down for large numbers of people.

We are calling on the government to commission a review into the use of antidepressants. The review should examine how antidepressants are prescribed, whether alternatives or additional support are offered, and whether those taking them receive regular reviews. Poor mental health has a huge impact on society and individuals and is something that needs urgent attention.

Rebecca Gill

Director of policy, research and communications, Platform 51

• It may seem obvious that traumatic events in our lives can make us depressed, but the study by King's College London highlights how damaging such traumas can be when experienced during childhood. We should all be concerned at how abuse and neglect creates a painful legacy that can last a lifetime, increasing our chances of experiencing episodes of depression. This study is not all doom and gloom, however, as it indicates early intervention in the form of family and other therapy may reduce the damage. This is particularly significant when we hear of nationwide cuts in child and adolescent mental health services. How short-sighted this is in the light of such convincing research.

Marjorie Wallace

Chief executive, SANE

DepressionMental healthHealthMedical researchWomenDrugsDrugs policyguardian.co.uk

Benefits of daily exercise are comparable to giving up smoking

Posted by on August 17, 2011 Comments Off

Researchers estimate that persuading inactive people to take up light, daily exercise could have a similar effect on a population's mortality rates as a smoking cessation programme

Exercising for just 15 minutes a day can increase your life expectancy by three years compared with doing little or no exercise, according to a major study of more than 400,000 people.

The benefits of physical activity are well-documented, and the UK government recommends that adults get at least two and half hours of exercise per week. In the latest study, scientists wanted to examine whether smaller amounts of exercise could also confer health benefits.

The researchers collected data on how much exercise was undertaken over the course of eight years by more than 400,000 people in Taiwan. By categorising the participants into bands of overall activity ranging from "inactive" to "very high", they could directly compare health outcomes based on exercise levels.

Those who exercised for an average of 92 minutes per week had a 14% overall reduced risk of mortality and a 10% reduced risk of cancer compared with people in the "inactive" group. Every additional 15 minutes of exercise above and beyond the minimum amount further reduced mortality risks by 4% and risks of death from cancers by 1%.

"These benefits were applicable to all age groups and both sexes, and to those with cardiovascular disease risks," wrote the researchers in the Lancet. "Individuals who were inactive had a 17% increased risk of mortality compared with individuals in the low-volume group."

Dr Chi-Pang Wen of the National Health Research Institutes in Taiwan and Dr Jackson Pui Man Wai of the National Taiwan Sport University, who led the study, said that if inactive individuals in Taiwan were to engage in low-volume daily exercise, "one in six all-cause deaths could be postponed – mortality reductions of similar magnitude have been estimated for a successful tobacco control programme in the general population."

They added: "If the minimum amount of exercise we suggest is adhered to, mortality from heart disease, diabetes, and cancer could be reduced. This low volume of physical activity could play a central part in the global war against non-communicable diseases, reducing medical costs and health disparities."

Professor Neville Owen, head of the behavioural epidemiology laboratory at Baker IDI Heart and Diabetes Institute in Melbourne said the findings were "intriguing" but that physical activity for leisure was a rare commodity in many adult populations. In Australia, the USA and Canada, he said, leisure-time physical activity drops off rapidly from early middle age and is simply not on the agenda for a large proportion of the population.

"In these chronically inactive populations, much of the problems that we are seeing can be attributed to people being stuck for long periods of time in front of screens for work and entertainment, and stuck in automobiles to get to and from work," said Owen.

"Thus, there is very little functional physical activity in people's lives, and many adults will sit for 10 or 12 hours a day. The real action is in promoting physically active transport and a range of initiatives that will help people to reduce the vast amounts of time that they spend sitting."

Medical researchHealthHealth & wellbeingAlok Jhaguardian.co.uk

Adding caffeine to sunscreen could guard against skin cancer

Posted by on August 16, 2011 Comments Off

Caffeine may help protect against some skin cancers by promoting the destruction of cells damaged by sunlight

Scientists have worked out how caffeine might protect against certain skin cancers – a finding that could lead to better sunscreens.

The research, conducted in mice, suggests that caffeine changes the activity of a gene involved in the destruction of cells that have DNA damage and are therefore more likely to become cancerous. The scientists said this may lead to new ways of preventing skin cancer, though other experts cautioned that it did not mean coffee lovers were better protected against the disease.

Skin cancer is a common disease. According to Cancer Research UK, around 100,000 cases of non-melanoma were registered in the UK in 2008, and just under 12,000 cases of the more dangerous malignant melanoma. These cancers can be caused by over-exposure to ultraviolet light from the sun, which can damage the DNA of skin cells, leading to errors when the cells divide.

The overall protective role of caffeine against cancers has been noted in previous studies, but Allan Conney of the department of chemical biology at Rutgers University in New Jersey wanted to find the specific molecular mechanisms behind it. He suspected that the response might involve a gene called ATR, which is suppressed when caffeine molecules are around. This suppression encourages the death of DNA-damaged cells.

Conney tested the idea by creating genetically modified mice whose ATR genes were deficient and exposing them to ultraviolet light until they developed skin cancer. After 19 weeks of UV exposure, he found that these mice developed 69% fewer tumours than those that had fully functioning ATR genes. In addition, tumours in the GM mice developed three weeks later than in standard mice.

After 34 weeks of UV exposure, all the mice had developed tumours, mainly a type of non-melanoma cancer called squamous cell carcinoma (SCC). The results were published on Monday in the Proceedings of the National Academy of Sciences.

"All of this suggests the possibility that caffeine, possibly [applied to the skin], would have an inhibitory effect on sunlight-induced skin cancer," said Conney. "In addition to the effects on the ATR pathway, caffeine also has sunscreening properties."

SCCs are less common than the other type of non-melanoma cancer, called basal cell carcinomas, but it's the former that are more dangerous. "People rarely die from basal cell carcinomas, but you need more invasive cutting to get it out," said Conney. "There's more disfiguration with basal cell than squamous cell. It's the squamous cell cancers that can metastasise and are more dangerous."

Jessica Harris, a health information manager at Cancer Research UK, pointed out that Conney's study examined how caffeine affected genes when it was directly applied to the skin, rather than ingested. "It didn't look at the effects of drinking coffee, so doesn't tell us whether or not this could reduce the risk of skin cancer," she said.

Studies looking at coffee consumption and cancer in large groups of people have provided mixed results, she added. "Some have found that coffee drinking may slightly reduce the risk of certain types of cancer, but the evidence is not yet strong enough to be certain, and these effects tend to be seen among people who drink very large amounts."

The best way to reduce the risk of skin cancer, said Harris, "is to enjoy the sun safely, taking care not to burn by using a combination of shade, clothing and sunscreen."

Dot Bennett, a professor of cell biology at St George's, University of London, said that any move to add caffeine or related molecules to sunscreens should be undertaken with care. "First one might want to check there is no adverse effect of caffeine on the incidence of other cancers, especially melanoma (pigmented skin cancer), which kills over four times as many people as [squamous cell carcinoma]. But caffeine lotion might promote tanning a little, since this family of molecules stimulates pigment cells to make more pigment."

CancerMedical researchGeneticsCancerSkin cancerHealthHealth & wellbeingAlok Jhaguardian.co.uk
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