Full disclosure: I just finished a cup of black coffee, and it was damn fine. (And yes, I make Twin Peaks references wherever possible.)
So it is with vigorous jumping up-and-down motions, aided surely by the caffeine, that I write about a team's findings from the University of Washington and Rutgers University that caffeine can help lower one's chances of UV-associated skin cancer by inhibiting a DNA repair pathway, essentially helping cells die after exposure to sunlight.
The team reports on this "protective effect of caffeinated beverage intake" in the August 15 issue of the Proceedings of the National Academy of Sciences.
Studies have already shown a reduced risk of skin cancer in those who drink caffeinated beverages. In 2007, for instance, almost 94,000 women participated in a study that found that those who drank caffeinated coffee daily had a 10 percent lower risk of nonmelanoma skin cancer, while those who drank six or more cups daily had an almost 40 percent reduction in risk.
Studies in mice have found the same link, using either ingested or topically applied caffeine, prompting researchers to wonder if adding caffeine to sun block might help improve the efficacy of that topical treatment.
In this study, the team was able to uncover the mechanism by which caffeine helps lower one's risk of skin cancer. The caffeine molecule itself is already known to behave as a natural sunscreen, but the stimulant also has an effect on DNA.
Caffeine, it turns out, inhibits the activity of a protein kinase--think of this as a family of enzymes--called ataxia telangiectasia and Rad3-related (more commonly referred to as ATR for obvious reasons). ATR is sensitive to incomplete DNA replication, so when it senses damaged DNA, it sends signals to the damaged cells to stop dividing. This interruption of normal cellular mitosis helps these damaged cells become cancerous.
By inhibiting this ATR activity, caffeine essentially helps cells die from the damage caused by UV exposure. Sounds bad, but as it turns out this preemptive measure is far better than letting those damaged cells become cancerous.
While this particular study was performed on mice, and while the researchers have yet to actually test topical application of caffeine, it is a major step forward in understanding precisely how caffeine is reducing skin cancer rates in mice and humans.
And as biophysicist Douglas Brash of Yale University's School of Medicine tells The Scientist, understanding the mechanism opens the door for developing other treatments that don't even need to use caffeine: "Caffeine was an interesting historical way of discovering this mechanism, but now that we know the mechanism...maybe we hunt for some other drug that's more specific."
Researchers are already testing drugs that target the ATR pathway to treat solid cancers; skin cancer could now be added to the list.
Corrected at 3:16 p.m.: This story initially gave an incorrect name for the school where this research took place. The team is made up of scientists at University of Washington and Rutgers University.