Understanding What Causes Lung Cancer

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Lung cancer is a type of cancer that primarily affects the lungs, but it may also spread to other areas of the body. In 2007, lung cancer was responsible for 29 percent of all cancer deaths and about 15 percent of all cancer diagnoses. It is the number one cancer-related cause of death, and the second most diagnosed next to prostate and breast cancer. Knowing what causes lung cancer can help patients avoid developing it. Not all lung cancer cases are preventable, but many are.

How Does Lung Cancer Occur?

The causes of lung cancer result in the DNA of lung cells mutating. This causes the cell to be unable to die and unable to correct DNA damage. A variety of factors can cause these mutations. The majority of lung cancer cases are caused by inhaling carcinogenic substances.


Carcinogens are substances directly responsible for aiding or promoting cancer due to damaging DNA. Examples of carcinogens include tobacco, arsenic, asbestos, car exhaust fumes, and radiation, such as x-rays and gamma rays. Free radicals form when a person is exposed to carcinogens and they try to “steal” molecules and electrons from the body. They affect how a cell normally divides and functions, and they damage cells. Inhaling tobacco smoke carcinogens and smoking accounts for about 87 percent of lung cancers. Second-hand smoke exposure can also cause lung cancer due to damaging cells.


Some lung cancer cases developed as a result of a genetic predisposition inherited from family. It is possible for a fault within a gene to make a person statistically more likely to fall victim to lung cancer. Being born with specific genetic mutations can also make a person more likely to developing lung cancer at some point in his or her life. In some cases, genetic predispositions greatly increase a person’s risk from being exposed to certain environmental factors, and in others, they are thought to directly cause this type of cancer.

Radon Gas

Radon gas can be found naturally occurring in soil and rocks. This type of gas may cause lung cancer via causing lung damage if this gas leaks into the person’s home. Those who are concerned about radon gas in their home can test for it with an inexpensive kit that works to measure the levels of radon gas.


Asbestos fibers are silicate fibers. Following exposure to asbestos these fibers can remain in the lung tissue for the rest of a person’s life. In the United States, asbestos is currently banned, but it is still around awaiting removal. Mesothelioma, a type of cancer affecting the abdominal cavity lining, and lung cancer can both develop as a result of asbestos exposure.

Other Possible Causes

Knowing what causes lung cancer is important and there are other possible causes. These include air pollution, heavy metals, pesticides, and a personal history of lung cancer in the past.

Certain diseases and conditions put people at an increased risk, such as chronic obstructive pulmonary disease, tuberculosis, and other lung diseases.


National Cancer Institute. (2011). Lung Cancer: Prevention, Genetics, Causes. Retrieved on January 11, 2011 from the National Cancer Institute: https://www.cancer.gov/cancertopics/prevention-genetics-causes/lung

Medical News Today. (2011). What is Lung Cancer? Retrieved on January 11, 2011 from Medical News Today: https://www.medicalnewstoday.com/info/lung-cancer/