Daily Archives: November 29, 2017

The link between cigarette smoking and increased risk of lung cancer is well-established. Recent studies are giving researchers more insight into the causes of the connection as well as possible methods of treatment.

What Causes Genetic Abnormalities?

Gene behavior is driven by DNA code, but it can also be affected by other external factors. These events, such as those brought on by exposure to cigarette smoke, are known as epigenetic changes.

Researchers at Johns Hopkins Kimmel Cancer Center in Baltimore grew human bronchial cells, the same type that line airways in the lungs, and bathed them daily with a liquid form of cigarette smoke. This procedure went on for 15 months, making it the equivalent of smoking one to two packs of cigarettes a day for 20 to 30 years.

How Smoking “Primes” Cells for DNA Damage

After only 10 days, the smoke-exposed cells sustained more DNA damage than unexposed cells. Over the next three months, the exposed cells showed a significant increase in EZH2, which is a hormone that silences genes.

EZH2 is also a precursor to methylation, in which tiny methyl groups are added to the start of a gene’s DNA code. As a result, tumor suppression genes are silenced and thereby unable to prevent the uncontrolled cell growth of cancer. Smokers who quit show a lower level of methylation, which can decrease their risk of cancer.