Be good to your skin, it’s the first line of defence
Skin cancer causes almost 160 deaths a year in Ireland, and can be much more difficult to treat than other cancers, so why do so many of us take risks with it?
Skin is the largest organ of the body, and makes up about 15 per cent of our body weight. Photograph: Getty Images
It is exquisitely tailored, smooth and beautifully finished yet hard-wearing, fully water-proof and breathable. It also has all the extras you might want, from UV protection to temperature control.
No this isn’t a miracle fabric or the latest in fashion. We are talking about skin. It is remarkable stuff, the largest organ of the body. It makes up about 15 per cent of our body weight and if spread out would cover 1½-2sq m.
Most of us don’t recognise skin as a key organ. Mostly we just ignore it, but we also put it at risk by overexposing it to the sun. However, if you treat it right it will last a lifetime.
“It is a vital organ in terms of being a package that holds the body together and also in terms of defence,” says Prof Bryan Hennessy, professor of medical oncology at the Royal College of Surgeons in Ireland. “People talk about the immune system but they forget skin is the first layer of the defence system.”
This time of year we benefit from skin’s ability to regulate our temperature on warm days, producing perspiration that evaporates to help us shed unwanted heat.
There is another protective function that has implications for our very lives. “Protective factors help prevent the skin from being damaged by ultra-violet light exposure from the sun,” says Prof Jochen Prehn, professor of physiology at the Royal College of Surgeons in Ireland and director of its centre for systems medicine. Both he and Hennessy are part-funded by the Irish Cancer Society.
UV radiation easily penetrates the epidermis or outer surface of the skin to reach the inner layers or dermis. These layers hold nerve endings; sweat glands; hair follicles; and skin pigment cells called melanocytes, which release melanin, the substance that makes you tan and protects your skin by absorbing UV.
However, when we are careless with the sun and repeatedly receive too much UV, we can get more than sunburned skin. DNA in the melanocytes can be damaged to trigger skin cancer – melanoma – which causes almost 160 deaths a year in Ireland, according to the National Cancer Registry.
And it can be UV from any source. Irish people are “literally risking their lives” when they use sunbeds, the Department of Health said in a statement last week. The Government ban on use of sunbeds for those under 18 came into force this month.
“A lot of what is going on is still not understood but UV is known to be damaging to DNA and so excessive exposure does result in changes that can transform into cancer cells,” says Hennessy.
Melanoma presents a significant risk, because it tends to spread cancer to other tissues, making treatment much more difficult. Research is under way to find better ways to treat this difficult disease.
Hennessy worked with Prof William Gallagher, professor of cancer biology at University College Dublin and other colleagues including Dr Máirín Rafferty at UCD. “We were trying to find proteins or other factors that drive the disease and also find markers that could predict how aggressive the disease will be,” says Rafferty. “Being able to predict overall survival has an impact on treatment. If you know it is a more aggressive form, then the treatment will be aggressive.”
Identifying aggressive forms
The research led to a campus company, OncoMark Ltd, based at NovaUCD with Rafferty serving as chief executive and Gallagher as chief scientific officer. It is looking at melanoma but also cancers of the breast, prostate and colon.
“We are working in a research phase, working up some of those biomarkers to develop them into a clinical assay to identify those patients who have a more aggressive form,” she says.
The company employs 12 researchers and is involved in six ongoing international research projects funded through the EU.
More research into melanoma is under way at the college under Dr Markus Rehm, whose postdoctoral research fellow Dr Max Wuerstle describes the work. He is a computational biologist who uses mathematical models and computers to analyse data coming from melanoma drug trials and tissue culture tests.
For decades chemotherapy, and the drug dacarbazine, has been a standard treatment for melanoma, but many new drugs have emerged, says Wuerstle.
“I am looking for markers via modelling which will help us to identify patients who will respond to treatment and those who won’t. We hope the clinical data will help us predict for a given patient which treatment would work best,” he says.
He is funded via EU programmes.
For good advice on sun exposure, visit cancer.ie/reduce-your-risk/sunsmart
LIFE-SAVING ORGAN: SWEAT AND GOOSE BUMPS
Your skin is only 1mm or 2mm thick, but it provides a collection of life-saving services that protect us from the big bad world.
On the macro scale, skin prevents water loss from the body, something that can put a life at risk, for example in the event of large-scale burns. It also provides a barrier that keeps bacteria and other pathogens from breaking in to colonise tissues inside.
On the micro scale, fatty acids released at the skin’s surface are able to kill off some of these invaders. “The pH [acidity] of the skin is the very first line of defence,” says Prof Bryan Hennessy of the Royal College of Surgeons in Ireland.
It also provides other life-saving services. For example, nerve endings respond to heat, pain, cold, pressure and itch, which helps us to avoid damage to the skin and to ourselves.
One of the most important of these protective features at this time of year relates to sun exposure.
Skin has a built-in way of protecting itself against the damage caused to DNA by ultra-violet light through the release of a pigment, the stuff that tans your skin after sun exposure. It is also vital for temperature control. When the body gets too warm the sweat glands imbedded in it – at more than 50 per square centimetre – go into action, delivering perspiration that evaporates to cool the body.
Goose bumps provide the opposite function, helping to generate heat through the muscle contractions of the hairs in the skin. It is also self repairing, closing up cuts and punctures in its surface within days to ensure the barrier remains intact.