Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started
My Medicine

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Cancer Health Center

Font Size

Genetic Map Reveals Mutations From Cancer

Gene Mutations Show Roles of Sunlight and Smoking in Cancer
WebMD Health News
Reviewed by Louise Chang, MD

Dec. 16, 2009 -- The first genetic maps of lung cancer and melanoma reveal the pivotal role of smoking and sunlight in triggering these two deadly forms of cancer.

In two new studies, researchers have sequenced the genome and mapped the entire series of thousands of genetic mutations that are not inherited but accumulate in the cells to cause small-cell lung cancer and melanoma.

The results show most of the 23,000 gene mutations associated with small-cell lung cancer are caused by the cocktail of chemicals found in cigarettes.

"On the basis of average estimates, we can say that one mutation is fixed in the genome for every 15 cigarettes smoked,” says researcher Peter Campbell, of the Cancer Genome Project at the Wellcome Trust Sanger Institute in Cambridge, England, in a news release.

More than 33,000 gene mutations were associated with melanoma, a rare but deadly form of skin cancer responsible for most skin cancer deaths.

Researchers say ultraviolet (UV)-light-induced gene mutations caused by exposure to sunlight were responsible for the vast majority of these mutations.

"Indeed because of the clarity of the genome data, we can distinguish some of the early, UV-induced mutations from the later mutations that do not have this signature, presumably occurring after the cancer cells spread from the skin to deeper tissues,” says Campbell.

"These are the two main cancers in the developed world for which we know the primary exposure," says researcher Mike Stratton, also of the Wellcome Trust Sanger Institute, in the release.

"For lung cancer, it is cigarette smoke and for malignant melanoma it is exposure to sunlight. With these genome sequences, we have been able to explore deep into the past of each tumour, uncovering with remarkable clarity the imprints of these environmental mutagens on DNA, which occurred years before the tumour became apparent,” says Stratton.

"We can also see the desperate attempts of our genome to defend itself against the damage wreaked by the chemicals in cigarette smoke or the damage from ultraviolet radiation," Stratton says."Our cells fight back furiously to repair the damage, but frequently lose that fight."

Today on WebMD

Colorectal cancer cells
New! I AM Not Cancer Facebook Group
Lung cancer xray
See it in pictures, plus read the facts.
sauteed cherry tomatoes
Fight cancer one plate at a time.
Ovarian cancer illustration
Real Cancer Perspectives
Jennifer Goodman Linn self-portrait
what is your cancer risk
colorectal cancer treatment advances
breast cancer overview slideshow
prostate cancer overview
lung cancer overview slideshow
ovarian cancer overview slideshow
Actor Michael Douglas