Although environmental and lifestyle factors often cause lung cancer, the disease can sometimes be genetic. Some genetic mutations that contribute to lung cancer run in families, but others do not.

The World Health Organization (WHO) states that lung cancer was the second most common cancer worldwide in 2020. In this year, it caused 1.8 million deaths, making it the most common cause of death due to cancer.

Both genetic and environmental factors can cause lung cancer. However, smoking remains the primary cause of lung cancer, being responsible for about 80–90% of cases.

Some experts estimate that a genetic predisposition to lung cancer contributes to approximately 8% of cases. Some of these genetic risk factors are inherited, meaning that they run in families.

However, other genetic changes are not inherited. A person’s genes may mutate because of environmental factors, such as smoking and exposure to pollution.

Read more to learn about the genetic causes of lung cancer, whether or not it runs in families, and the genetic testing options.

A family standing together. Lung cancer has genetic components, some of which may be hereditary.Share on Pinterest
Taro Hama @ e-kamakura/Getty Images

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 may contribute to a person’s risk of developing lung cancer include:

  • Radon exposure: This radioactive gas exists naturally in the environment, and because it is colorless and odorless, it can go undetected. About 1 in 15 homes in the United States are 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.
  • Particle pollution: Particles from exhaust smoke, dust, and other sources enter the air and can increase the risk of lung cancer.
  • Genetic factors: Individuals with certain genetic factors may have an increased risk.

In some cases, gene mutations that contribute to lung cancer can be hereditary, which means that a person is more likely to develop the disease if it has affected a close relative.

A 2011 study suggests that an individual’s genes are more likely to contribute to an increased chance of lung cancer if they are young and have never smoked.

However, lung cancer can also run in families because of shared environmental factors and lifestyle habits. For example, families may live in an area with high amounts of hazardous chemicals.

Smoking can also affect family members. Research has shown that children living with people who smoke are more likely to smoke. Additionally, living with someone who smokes exposes children to harmful chemicals.

Research suggests that both genetic and environmental factors influence a person’s lung cancer risk. However, doctors do not fully understand the genetic factors responsible for lung cancer.

Individuals may 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.

Inherited genetic changes

Some genetic factors are inherited. Researchers know that DNA changes in a particular chromosome, such as chromosome 6, can influence a person’s lung cancer risk in various 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 due to an epidermal growth factor receptor (EGFR) mutation. EGFR helps cells grow, and a mutation that affects it can make the cells grow out of control, causing cancer.

EGFR mutations are responsible for about 32% of non-small cell lung cancers worldwide. Non-small cell lung cancer is the most common type of lung cancer, accounting for 80–85% of all lung cancers.

Among never-smokers, this gene mutation is most common in females 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 how the cells grow, divide, and die.

However, some genetic changes are not attributable 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 gene
  • RB1 tumor suppressor gene
  • TP53 tumor suppression gene

Researchers are continuing to investigate which genetic mutations cause lung cancer.

Doctors may 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.

Additionally, the doctor may check for specific mutations that indicate which treatment will be best. The individual can then undergo targeted treatment, which may be more effective.

Doctors may also use a blood test to identify biomarkers that will guide their treatment decisions.

Learn more about genetic testing’s role in treating lung cancer.

An individual can take steps to reduce their risk of developing lung cancer. These include:

Avoid tobacco smoke

Refraining from smoking and avoiding secondhand smoke can reduce a person’s lung cancer risk. Even if someone has smoked for years, quitting smoking can reduce their risk of developing lung cancer. It is never too late to stop.

Learn more about support for stopping smoking.

Reduce radon exposure

Radon gas is a leading cause of lung cancer. People can reduce their exposure by testing radon levels in their home. Certain occupations, such as working in underground mines, may increase a person’s risk of radon exposure.

Learn more about radon exposure.

Avoid carcinogens

People should take precautions to protect themselves against toxic chemicals in the workplace. For example, they should use face masks, eye protection, and any other protective wear that their employer recommends.

Learn more about avoiding carcinogens.

Lung cancer is one of the most common forms of cancer, and both environmental and genetic factors can play a role in its development.

If an individual has a family history of lung cancer, they may be more likely to get the disease. This increased risk can be due to genetic mutations or shared lifestyle and environmental factors, such as smoking and exposure to carcinogens.

An individual may inherit genetic mutations or acquire them because of exposure to environmental toxins. Sometimes, genetic changes have no trigger and appear random. Scientists do not yet fully understand the genetic factors causing lung cancer.