What are genes? Genes are pieces of DNA inside each of your cells. They tell the cell what to do and how to divide, which is the way cells multiply. Scientists give each gene a name to remember them.
What are gene mutations? Mutations are permanent changes in your DNA. They can affect how a cell works. For example, they may have an impact on how it grows and divides.
Why do you get gene mutations? Sometimes mutations are passed to you from your parents. These are called "inherited" or "hereditary" gene changes. In lung cancer, mutations usually aren't inherited. Instead, the changes are what doctors call "acquired" mutations. They happen during your lifetime.
Things outside your body, like breathing in tobacco smoke, lead to gene mutations. Air pollution, certain chemicals, and radon gas are also causes. In a small portion of lung cancer cases, these acquired gene mutations are just random things that happen. Your DNA changes inside your cell without any outside trigger.
How do gene mutations cause cancer? Changes in your DNA can have two big effects:
"Turn on" the genes that help your cells grow, divide, or stay alive.
"Turn off" the genes that make sure cells divide or die at the right time.
The result of all these changes to your genes: Some cells become cancerous and grow out of control.