Is Lung Cancer Genetic?

Smoking is the No. 1 cause of lung cancer, but many people who get this cancer never smoked. That includes about 20% of people who die from lung cancer each year in the U.S. Apart from smoking, things in your environment and your genes can also raise your risk.

If you have a parent, brother, or sister who's had lung cancer, you're two or three times more likely to get this cancer than someone without a family history of the condition. But you need to put that risk in perspective. Your overall risk is still very low. Having a parent or sibling with lung cancer doesn't mean you'll get the disease. Only about 8% of lung cancers run in families.

Still, it's good to know your family history and discuss it with your doctor, just like with any other health concern.

Genes and Lung Cancer

A small number of lung cancers are linked to genes. You may already know that genes are pieces of DNA that carry the instructions your body needs to work. Genes control how your cells grow, divide, and die.

Oncogenes are a type of gene that helps cells grow and divide. Tumor suppressor genes stop cells from dividing or make them die off when you don't need them anymore.

Changes called mutations in these genes allow cells to divide and divide until they form tumors. That's how cancer starts.

Some gene mutations make it harder for your body to get rid of cancer-causing chemicals. Others prevent damaged DNA from repairing itself.

Most gene changes that raise lung cancer risk happen during a person's lifetime. Rarely, someone inherits these mutations from their parents.

Genes are more likely to cause some types of lung cancer than others. For example, about 60% of people with lung adenocarcinomas have certain gene mutations.

If lung cancer runs in your family, genes may not be the only reason. A shared environment can also be part of the risk. For instance, if someone in your home smoked, that could put you at risk. The same is true if you and your family were exposed to the same cancer-causing chemicals.

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Screening Tests

Should you get tests to look for lung cancer if you don’t have symptoms but do have a family history? Not necessarily.

The U.S. Preventive Services Task Force only recommends lung cancer screening for people who are ages 55 to 80 and:

  • Smoke now or quit within the past 15 years
  • Smoked an average of one pack of cigarettes a day for 30 years (or two packs a day for 15 years)

If you meet these guidelines, you should get a low-dose CT scan once a year, even if no one in your family has lung cancer.

Gene tests can also help your doctor find the right treatment for you if you do get lung cancer. About 10% of people with non-small-cell lung cancer (NSCLC) have a mutation in the EGFR gene, and 25% have a mutation in the KRAS gene. There are medications that target these gene changes.

Ways to Lower Your Risk

Though you can't change your genes, you can do other things to lower your odds of getting lung cancer.

If you smoke, talk with your doctor for tips to help you quit for good. About 90% of lung cancer cases are directly linked to smoking.

Secondhand smoke is another risk factor. Stay away from anyone who smokes, so you don't breathe in cancer-causing chemicals.

In nonsmokers, the No. 1 cause of lung cancer is radon gas. Radon is a gas in the soil of some parts of the country. It can seep into homes and get into the air. You can't smell radon gas. The only way to know your home has it is to test for it.

Asbestos, diesel exhaust, and certain heavy metals are also linked to lung cancer. If you work around these substances, ask your employer for ways to protect yourself.

It’s also a good idea to get more fruits and vegetables in your diet. Although no specific vitamin or mineral has been shown to lower lung cancer risk, eating plant foods that are naturally rich in antioxidants and other nutrients may help lower your risk for lung cancer, along with many other diseases. Food is the best way to get these nutrients.

WebMD Medical Reference Reviewed by Carol DerSarkissian on October 17, 2019

Sources

SOURCES:

American Cancer Society: "Lung Cancer Risks for Non-Smokers," "What Causes Lung Cancer?"

American Lung Association: "What Causes Lung Cancer."

Annals of Oncology: "Fruits, vegetables and lung cancer risk: A systematic review and meta-analysis."

Genetics Home Reference: "Lung Cancer."

Oncology Letters: "Familial Risk for Lung Cancer."

Memorial Sloan Kettering Cancer Center: "Lung Cancer Genomic Testing (EGFR, KRAS, ALK)."

U.S. Preventive Services Task Force: "Lung Cancer: Screening."

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