WASHINGTON (AFP) - Coffee has been shown to reduce the risk of skin cancer by helping kill off damaged cells that could otherwise turn into tumors, according to a US study published on Monday.
The findings indicate that moderate caffeine drinking, or perhaps even applying coffee to the skin, could be useful in warding off non-melanoma cancer, the most commonly diagnosed of all skin cancers.
Using mice that had been genetically altered to suppress a protein enzyme called ATR, researchers showed that the mice were able to fend off cancer even when exposed to ultraviolet light.
Previous studies have suggested that drinking about a cup of caffeinated coffee per day has the effect of suppressing ATR and triggering the die-off of cells harmed by UV rays.
The altered mice eventually did develop cancer, but three weeks later than normal mice, according to the study published in the Proceedings of the National Academy of Sciences.
After 19 weeks of ultraviolet light exposure, the engineered mice showed 69 percent fewer tumors and four times fewer invasive tumors than the control group.
However, the protective effects only went so far. After 34 weeks of UV exposure, all the mice developed tumors.
"Eventually, if you treat them long enough, the mice will develop cancer so it is not 100 percent protection forever," Allan Conney, one of the study's authors, told AFP.
"Really, with almost any carcinogen, eventually all the animals will develop tumors," added Conney, who is director of the Susan Lehman Cullman Laboratory for Cancer Research at Rutgers University in New Jersey.
Conney and his team were able to confirm their hypothesis that caffeine -- when consumed or applied to the skin -- works by inhibiting ATR. Now they say more studies are needed to see how it may work on humans.
"We want to see whether caffeine has an effect in people when you give it topically," he said.
"Caffeine might become a weapon in prevention because it inhibits ATR and also acts as a sunscreen and directly absorbs damaging UV light."
Skin cancer is the most prevalent cancer in the United States, with more than one million new cases each year, according to the National Cancer Institute.
Non-melanoma types of skin cancer, including basal cell and squamous cell types, are the most commonly diagnosed and are often treatable if detected early.
Previous studies have shown coffee drinkers tend to have fewer incidences of breast, uterine, prostate and colon cancers, but the beneficial effects are not seen in people who drink decaffeinated coffee.
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커피, 피부암 예방에 효과
커피가 종양으로 발전할 위험이 있는, 손상된 세포를 죽 여 피부암 위험을 줄여준다는 연구 결과가 나왔다.
커피를 적당히 마시거나 피부에 바르면 악성인 흑색종을 제외한 피부암을 예방 하는 데 도움이 된다는 게 15일(현지시각) 미국 국립과학원회보(PNAS) 인터넷판에 실린 연구 결과를 통해 확인됐다.
카페인을 섭취하거나 피부에 발랐을 때 ATR이라는 단백질을 억제하는 효과가 있 다고 가정한 연구진은 ATR를 억제하도록 유전적으로 변형된 쥐를 이용한 실험에서 쥐가 자외선에 노출됐을 때도 암을 막는다는 것을 입증했다.
이는 카페인이 든 커피를 하루에 한 잔씩 마시면 ATR를 억제하고 자외선에 손상 된 세포를 죽이는 효과가 있다는 기존 연구를 뒷받침하는 성과다.
이번 실험에서 유전적으로 변형된 쥐를 자외선에 19주 동안 노출했을 때 암에 걸릴 확률이 대조군보다 69% 낮다는 결과가 나왔으며 ATR를 억제하도록 변형된 쥐 역시 결국 암에 걸렸지만, 그렇지 않은 쥐보다 발병이 3주 지체됐다.
미 뉴저지 주(州) 러트거스대학 암연구소의 앨런 코니 등이 주도한 연구진은 카 페인이 인체에서도 피부암 예방 효과를 내는지 더 연구하고자 한다고 설명했다.
한편, 미 국립암연구소에 따르면 피부암은 미국인이 가장 많이 걸리는 암으로 매년 100만명 넘는 환자가 발생하는데 흑색종을 제외한 피부암이 가장 흔하며 초기 에 진단하면 치료할 수 있다.
