While scientists have known of hotspots, until now they did not know of ultra-sensitive hotspots. Researchers discovered these "hyperhotspots" in the human genome - in locations that are up to 170 times more sensitive to ultraviolet radiation (UV) from sunlight compared to the genome average. Since exposure to UV radiation is the major cause of skin cancer, screening the hyperhotspots could offer a new means of predicting a person's skin cancer risk. Named "cyclobutane pyrimidine dimer (CPD) hyperhotspots" after the type of DNA damage caused by ultraviolet light, these hyperhotspots can be thought of as "bullseyes" that attract damaging radiation. In the study, published in Proceedings of the National Academy of Sciences, they occurred most often in melanin-forming cells in human skin known as melanocytes - the cells in the skin where melanoma skin cancer originates.
The Yale University researchers designed a method for tagging sites of CPDs and used high-throughput DNA sequencing to map tags across the genome. They also developed a set of statistical methods for quantifying an individual site's overrepresentation of CPDs relative to the genome average. They discovered that the hotspots were located near genes, acting as a direct pathway for UV radiation to damage the cell. The sites where the Yale study identified hyperhotspots are the same DNA sequences that control the regulation of DNA into RNA and protein, which is how the cell regulates growth.
Hyperhotspots at sunburn levels of UV exposure in the pigment cells of a person's skin would be affected by UV radiation. A person would experience specific cell growth distortions from UV radiation in real time, not randomly or unpredictably and not weeks or years later, as was previously thought. The fact that evolution has not eliminated these bullseyes may be a tipoff that the cell uses hyperhotspots for sensing its environment. The existence of hyperhotspots suggests that mutations spawned by a carcinogen, such as UV radiation, are also not entirely random. Mutations related to gene regulation in melanoma tumors were present at CPD hyperhotspots 20,000 times more often than elsewhere.
Doctors currently lack an objective means of measuring skin cancer risk, relying typically on patients' memories of former sunburns. The study suggests new ways of assessing skin cancer risk. The most important factor for evaluating the risk is prior UV exposure. If doctors could take a small skin sample and examine the hyperhotspots, they could get a true picture of the DNA damage from prior sunburn at these sites and have a much better understanding of a patient's exposure history and skin cancer risk. High-risk individuals could be watched closely by a dermatologist so that skin cancers are detected early, when they are still curable. "These are 100 times more sensitive than other sites in the genome," says Douglas Brash, research leader and senior research scientist in therapeutic radiology and dermatology and a member of the Yale Cancer Center. "We had thought that DNA damage and mutations that cause cancer were rare events, and random, but this reveals that, at least for skin cancer, there are specific targets in the genome that are waiting to be hit by UV radiation."
Lower Your Skin Cancer Risk
Experts at Yale Cancer Center (YCC) and Yale School of Medicine (YSM) say unless you take the right precautions, sun exposure can damage your skin, causing wrinkles, age spots and even skin cancer. Just one sunburn during your youth doubles your chances of developing melanoma, the deadliest form of skin cancer.
Skin cancer experts with the American Academy of Dermatology say these tips can help you avoid sun damage and reduce your chances of getting skin cancer:
Avoid the sun’s peak hours
Plan your outdoor activities before or after the sun is at its strongest. The sun is most damaging to skin between 10 a.m. and 2 p.m.
If you've had skin cancer before, you should be checked annually by a dermatologist. Using a full-length mirror, scan your skin for spots that look suspicious - unusually shaped moles that are changing shape or are black, red or pink in color - and tell your physician.
Clothing made of tightly woven fabric with a high ultraviolet protection factor (UPF) rating can create a physical barrier that protects your skin from the sun. Long sleeves or pants, sunglasses and a hat with a wide brim will also help shade you.
Apply high SPF sunscreen generously
Apply sunscreen everywhere on your body, not just your face and upper arms. Use a broad-spectrum, water-resistant sunscreen - SPF 30 or greater - every day. Be sure it hasn’t expired and reapply every two hours as well as after swimming or sweating.
Seal your lips
Lip balms, glosses and sticks often contain SPF ingredients. Opaque lipsticks contain pigments that help block harmful rays. More opaque formulas protect better.
“Since skin cancer is the most common form of cancer in the United States - one in five people will be diagnosed with it in their lifetime - it’s important to practice sun safety before heading outdoors,” says Michael Girardi, MD, director of the Phototherapy Unit at YCC and professor of dermatology at YSM. “There is concern that rates of melanoma have been steadily rising over the last 30 years.”
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With over 30 years of writing and editing experience for newspapers, magazines and corporate communications, Kevin Kerfoot writes about natural health, nutrition, skincare and oral hygiene for Trusted Health Products’ natural health blog and newsletters.
Founder Ray Spotts has a passion for all things natural and has made a life study of nature as it relates to health and well-being. Ray became a forerunner bringing products to market that are extraordinarily effective and free from potentially harmful chemicals and additives. For this reason Ray formed Trusted Health Products, a company you can trust for clean, effective, and healthy products. Ray is an organic gardener, likes fishing, hiking, and teaching and mentoring people to start new businesses. You can get his book for free, “How To Succeed In Business Based On God’s Word,” at www.rayspotts.com.