Science Surgery: ‘How is skin cancer related to sun exposure?’


Our Science Surgical procedure sequence solutions your cancer science questions.

Jenny requested: “How is skin cancer related to sun publicity?”

“Once we discuss skin cancer, we’re truly speaking about a variety of differing types,” says Professor Richard Marais, a skin cancer professional and director of the Cancer Analysis UK Manchester Institute. “And for nearly all of those varieties, it’s very clear that the environmental carcinogen is daylight.”

Extra particularly, it’s the ultraviolet (UV) radiation given out by the sun that causes these cancers. Any such radiation can penetrate the skin and harm the DNA inside cells.

It’s this harm that may additionally trigger skin to change color.

“UV mild causes DNA harm which implies sure cells in your skin distribute a pigment referred to as melanin to different cells. This causes the skin to darken and is what individuals name a tan. You solely get the tan if in case you have the DNA harm,” says Marais.

Sun signatures and skin cancer

The hyperlink between UV radiation and skin cancer was found in levels. First, UV radiation was linked to specific kinds of DNA harm.

“Scientists would expose cells in a take a look at tube to UV mild after which have a look at the DNA for the kinds of modifications that occurred,” says Marais. “And so they had been ready to see that UV mild causes a selected kind of change within the DNA.”

Any such DNA harm (mutation) was completely different to that attributable to different carcinogens, resembling tobacco. In different phrases, UV radiation left a novel mark on the DNA, typically referred to as a ‘UV signature’.

It was this signature that led scientists to join sun publicity and skin cancer.

“When scientists had been ready to sequence huge numbers of tumours, they discovered that the very same mutations that had been outlined within the lab had been present in skin cancers,” says Marais.

Marais says that every skin cancer has on common round 30,000 DNA faults attributable to publicity to daylight.

“Now in fact, not all of those are what’s driving the cancer, however the extra mutations you will have the extra likelihood there is that you just’ll hit the mistaken combos of genes and you’ll get a cancer.”

Is all of it skin cancers?

Whereas most skin cancers are tied to sun publicity, there are some that don’t appear to share this hyperlink. One among these is a uncommon kind of cancer that develops on skin with out hair, referred to as acral skin.

“It’s the skin on the palms of the palms, the soles of the ft and beneath your nail beds the place you’ll be able to develop acral melanomas,” says Marais. “And round half of acral melanomas don’t appear to have a UV signature, which implies they aren’t attributable to UV mild.”

Marais says there are additionally a small variety of circumstances of the extra frequent skin cancers the place the UV signature within the tumour appears to be very low.

“The identical is true of different carcinogens like tobacco – round 10% of lung cancers aren’t attributable to smoking,” he provides.

Scientists are different elements that might contribute to skin cancer threat, together with our genes.

Is it simply daylight?

“Some individuals have the next predisposition to skin cancer, individuals with blonde hair and fairer skin for instance,” says Marais.

Folks with paler skin produce much less of the skin pigment eumelanin. This pigment particularly can assist defend cells from getting DNA harm by absorbing UV radiation.

However in accordance to Marais, it’s not a direct relationship between skin tone and hair color and melanin manufacturing. “It’s additionally about the remainder of your genetic make-up,” he says

This might embody DNA variants that have an effect on how successfully somebody’s cells are ready to restore DNA harm. Marais says that folks whose cells are much less ready to restore DNA harm have the next threat of growing skin cancer.

“It’s doubtless to be a mixture of many alternative issues.”

How a lot daylight?

When it comes to figuring out how a lot sun is an excessive amount of, Marais says there isn’t a transparent reply.

“What we do know is that in lab research, one shot of publicity is sufficient to improve the probabilities of getting skin cancer,” says Marais. “And from massive inhabitants research, we all know that the extra typically you burn the upper your likelihood is.”

Staying protected within the sun

One of the best ways to benefit from the sun safely and defend your skin is to use a mixture of shade, clothes and sunscreen.
Shade and clothes are simpler than sunscreen at defending your skin.

Go to our web site for extra data on methods to benefit from the sun safely.

Marais says it might be that every individual has a person threshold of injury.

“It’s a numbers recreation actually, you will have thousands and thousands and thousands and thousands of melanocytes in your skin,” says Marais. “And the extra you expose your self the extra doubtless it is that a type of cells will choose up the mistaken constellation of injury within the mistaken constellation of genes, and sadly that can lead to melanoma.”


We’d like to thank Jenny for asking this query. In case you’d like to ask us one thing, publish a remark under or e mail sciencesurgery@cancer.org.uk along with your query and first identify.

Extra on this subject


Related Articles

Leave a Reply

Back to top button