Cigarettes leave you with more than a smoky scent on your clothes and fingernails. A new study has found strong evidence that tobacco use can affect the activity of genes known to increase the risk of developing cancer. The finding may give researchers a new tool to assess cancer risk among smokers.
DNA isn't destiny. Chemical compounds that affect the functioning of genes can bind to our genetic material, turning certain genes on or off. These so-called epigenetic modifications can influence a variety of traits, such as obesity and sexual preference.
In the new study, published in Human Molecular Genetics, researchers analyzed epigenetic signatures in blood cells from 374 individuals enrolled in the European Prospective Investigation into Cancer and Nutrition. EPIC, as it's known, is a massive study aimed at linking diet, lifestyle, and environmental factors to the incidence of cancer and other chronic diseases.
Half of the group consisted of people who went on to develop colon or breast cancer 5 to 7 years after first joining the study, whereas the other half remained healthy.
The team, led by James Flanagan, a human geneticist at Imperial College London, discovered a distinct "epigenetic footprint" in study subjects who were smokers. Compared with people who had never smoked, these individuals had fewer chemical tags known as methyl groups a common type of epigenetic change on 20 different regions of their DNA.
When the researchers extended the analysis to a separate group of patients and mice that had been exposed to tobacco smoke, they narrowed down the epigenetic modifications to several sites located in four genes that have been weakly linked to cancer before. All of these changes should increase the activity of these genes, Flanagan said. It's unclear why increasing the activity of the genes would cause cancer, he said, but individuals who don't have cancer tend not to have these modifications.
The work may lead to new ways to assess cancer risks from smoking. The new study, Flanagan said, may make it possible for doctors to quantify a person's cancer risk simply through an epigenetic analysis of their DNA.
© Copyright The Sacramento Bee. All rights reserved.
Read more articles by Karl Gruber
What You Should Know About Comments on Sacbee.com
Sacbee.com is happy to provide a forum for reader interaction, discussion, feedback and reaction to our stories. However, we reserve the right to delete inappropriate comments or ban users who can't play nice. (See our full terms of service here.)
Here are some rules of the road:
Keep your comments civil. Don't insult one another or the subjects of our articles. If you think a comment violates our guidelines click the "Report Abuse" link to notify the moderators. Responding to the comment will only encourage bad behavior.
Don't use profanities, vulgarities or hate speech. This is a general interest news site. Sometimes, there are children present. Don't say anything in a way you wouldn't want your own child to hear.
Do not attack other users; focus your comments on issues, not individuals.
Stay on topic. Only post comments relevant to the article at hand.
Do not copy and paste outside material into the comment box.
Don't repeat the same comment over and over. We heard you the first time.
Do not use the commenting system for advertising. That's spam and it isn't allowed.
Don't use all capital letters. That's akin to yelling and not appreciated by the audience.
Don't flag other users' comments just because you don't agree with their point of view. Please only flag comments that violate these guidelines.
You should also know that The Sacramento Bee does not screen comments before they are posted. You are more likely to see inappropriate comments before our staff does, so we ask that you click the "Report Abuse" link to submit those comments for moderator review. You also may notify us via email at email@example.com. Note the headline on which the comment is made and tell us the profile name of the user who made the comment. Remember, comment moderation is subjective. You may find some material objectionable that we won't and vice versa.
If you submit a comment, the user name of your account will appear along with it. Users cannot remove their own comments once they have submitted them.