US research rewrites understanding of skin cancer
US scientists believe that new research has rewritten our understanding of how the sun's ultraviolet (UV) radiation causes skin tanning.
The work, in genetically engineered mice, could pave the way for new methods of preventing skin cancer, although Cancer Research UK pointed out that the best advice would always be to avoid UV damage in the first place.
Tanning, sunburn and skin cancer are all caused by UV damage to skin cells.
Tanning occurs when the sun's UV radiation stimulates the most common skin cells, known as keratinocytes.
These then release a hormone known as MSH which tells nearby melanocytes to produce a pigment called melanin, causing tanning.
Using a naturally-occurring compound derived from a plant, known as forskohlin, the researchers were able to simulate the chain of interactions that occurs when MSH stimulates melanocytes.
This created an effect similar to that of a sun tan, without exposing the skin to the sun's damaging UV rays.
The researchers noted that further research is required to see if the results of the study can be replicated in human skin.
Hazel Nunn of Cancer Research UK warned that any eventual products would be unlikely to replace the common-sense measures which provide the best defence against skin cancer, however.
"We welcome this advance in our understanding of the tanning process but it is important to point out that a tan-inducing cream alone would be unlikely to provide enough protection from sunburn to those with fair skin or to prevent skin cancer," she said.
"A UV-induced tan only provides protection equivalent to that of sunscreen with SPF4. "Cancer Research UK's SunSmart campaign urges people, especially those with fair skin, to avoid getting sunburnt by seeking shade and covering up with a t-shirt, hat and sunglasses when the summer sun is at its peak."
The research was conducted by the Dana-Farber Cancer Institute and Children's Hospital Boston and published in the journal Nature