While environmental and lifestyle factors often cause lung cancer, sometimes the disease can be genetic. Some genetic mutations that contribute to lung cancer run in families, but others do not.
The World Health Organization (WHO) states that in 2020 lung cancer was the second most common cancer worldwide. In this year, it caused 1.8 million deaths, making it the most common cause of death from cancer.
Both genetic and environmental factors can cause lung cancer. However, smoking remains the primary cause of lung cancer and accounts for approximately 80-90% of cases.
Some experts estimate that a genetic predisposition to lung cancer contributes to about 8% of cases. Some of these genetic risk factors are hereditary, meaning they run in families.
However, other genetic changes are not inherited. A person’s genes can mutate due to environmental factors, such as smoking and exposure to pollution.
Read more to learn about the genetic causes of lung cancer, whether it runs in families or not, and the genetic testing options.
Smoking is the most common cause of lung cancer. Exposure to secondhand smoke can also contribute to a person’s chances of developing lung cancer.
Individuals who smoke and also encounter environmental risk factors, such as radon, have an even higher risk.
Other factors that can contribute to a person’s risk of developing lung cancer include:
Radon exposure: This radioactive gas occurs naturally in the environment and because it is colorless and odorless, it can go undetected. About 1 in 15 homes in the United States is subject to radon exposure.Hazardous chemicals: Individuals who work with asbestos, uranium, cadmium, arsenic or various petroleum products have an increased risk of lung cancer.Pollution by particles: Particles from exhaust smoke, dust and other sources are released into the air and can increase the risk of lung cancer.Genetic Factors: Individuals with certain genetic factors may be at increased risk.
In some cases, gene mutations that contribute to lung cancer can be hereditary, meaning a person is more likely to develop the disease if they have affected a close relative.
A 2011 study suggests that a person’s genes are more likely to contribute to an increased risk of lung cancer if they are young and have never smoked.
However, lung cancer can also run in families due to shared environmental factors and lifestyle habits. For example, families may live in an area with high levels of hazardous chemicals.
Smoking can also affect family members. Research has shown that children who live with people who smoke are more likely to smoke. In addition, living with someone who smokes exposes children to harmful chemicals.
Research suggests that both genetic and environmental factors influence a person’s risk of lung cancer. However, doctors do not fully understand the genetic factors responsible for lung cancer.
Individuals can inherit genetic mutations from their biological parents that increase their risk of developing lung cancer. They can also acquire genetic mutations later in life from exposure to toxins, chemicals, or other environmental factors.
Hereditary genetic changes
Some genetic factors are hereditary. Researchers know that DNA changes in a particular chromosome, such as chromosome 6, can affect a person’s risk of lung cancer in several ways.
Some people may inherit genes that make them less able to break down the cancer-causing chemicals in tobacco smoke. Others may inherit an inability to repair their DNA, making them particularly vulnerable to radiation and cancer-causing chemicals.
Some cases of lung cancer occur as a result of a mutation in the epidermal growth factor receptor (EGFR). EGFR helps cells grow, and a mutation that affects it can cause the cells to grow out of control and cause cancer.
EGFR mutations are responsible for approximately 32% of non-small cell lung cancers worldwide. Non-small cell lung cancer is the most common form of lung cancer, accounting for 80-85% of all lung cancers.
Among non-smokers, this gene mutation is most common in women in East Asia.
Acquired Genetic Changes
An individual usually acquires, rather than inherits, the genetic changes that cause lung cancer.
People can get gene mutations from multiple sources. Exposure to certain environmental toxins can change the way the cells grow, divide and die.
However, some genetic changes are not due to an external cause and happen randomly.
Acquired gene changes can affect tumor suppressor genes. When these do not function properly, they cannot stop the growth of abnormal cells. Some tumor suppressor genes that can cause lung cancer include:
p16 tumor suppressor geneRB1 tumor suppressor geneTP53 tumor suppressor gene
Researchers continue to investigate which genetic mutations cause lung cancer.
Doctors can use genetic testing to diagnose and treat lung cancer. Genetic testing involves looking for specific biomarkers, or changes in genes, that give the doctor more information about a person’s lung cancer.
To perform genetic testing, the doctor takes a sample of the tumor and sends it to a lab, where technicians test the tumor tissue for abnormal DNA.
In addition, the doctor can check for specific mutations that indicate which treatment is best. The individual can then undergo targeted treatment, which may be more effective.
Doctors can also use a blood test to identify biomarkers that will guide their treatment decisions.
Learn about the role of genetic testing in lung cancer treatment.
An individual can take steps to reduce the risk of developing lung cancer. Of which:
Avoid tobacco smoke
Giving up smoking and avoiding secondhand smoke can reduce a person’s risk of lung cancer. Even if a person has smoked for years, quitting smoking can reduce the risk of developing lung cancer. It’s never too late to stop.
Read more about smoking cessation support.
Reducing exposure to radon
Radon gas is a leading cause of lung cancer. People can reduce their exposure by testing radon levels in their homes. Certain occupations, such as working in underground mines, can increase the risk of exposure to radon.
Learn more about radon exposure.
People should take precautions to protect themselves from toxic chemicals in the workplace. For example, they should use face masks, eye protection, and other protective clothing recommended by their employer.
Read more about avoiding carcinogens.
Lung cancer is one of the most common cancers and both environmental and genetic factors may play a role in its development.
If a person has a family history of lung cancer, they are more likely to develop the disease. This increased risk may be due to genetic mutations or shared lifestyle and environmental factors, such as smoking and exposure to carcinogens.
An individual can inherit or acquire genetic mutations due to exposure to environmental toxins. Sometimes genetic changes have no trigger and appear random. Scientists do not yet fully understand the genetic factors that cause lung cancer.