Researches at Rutgers have studied the theory that caffeine guards against certain skin cancers at the molecular level by inhibiting a protein enzyme in the skin, known as ATR.

Skin cancer is the most common form of cancer in the United States. Both basal cell and squamous cell carcinomas (cancer) are highly curable. In 2010 estimated new cases from skin (nonmelanoma) cancer in the United States have seen more than 1,000,000 cases according to the Center for Disease Control and Prevention. Melanoma; however, has been found to be deadly. 58,094 people in the United States were diagnosed with melanomas of the skin. About 65-90 percent of melanomas are caused by exposure to ultraviolet (UV) light.

Previous studies by scientists found that mice that were fed caffeinated water inhibiting ATR and then exposed to UVB radiation, which damaged skin DNA, were able to kill off a greater percentage of their badly damaged cells and had reduced the risk of cells becoming cancerous.

"Although it is known that coffee drinking is associated with a decreased risk of non-melanoma skin cancer, there now needs to be studies to determine whether topical caffeine inhibits sunlight-induced skin cancer," said Allan Conney, director of the Susan Lehman Cullman Laboratory for Cancer Research.

Rutgers researchers, with collaboration with researchers from University of Washington, studied how genetically modified and diminished ATR in one group of mice affects skin cancer.

The results show that genetically modified mice developed tumors slower than the un-modified mice. The genetically modified mice had 69 percent fewer tumors than regular mice and developed four times fewer invasive tumors. In contrast, both groups of mice, genetically modified and regular mice, when exposed to chronic ultraviolet rays for an extended time developed tumors.

"What this seems to indicate is that inhibiting the ATR enzyme works best at the pre-cancerous stage before UV-induced skin cancers are fully developed,” said Conney. He continued “Caffeine might become a weapon in prevention because it inhibits ATR and also acts ad as a sunscreen and directly absorbs damaging UV light."