Introduction Many studies show a strong link between PCB exposure and the development of lung cancer, both in humans and animals. Occupational studies have found statistically significant increases in lung cancer correlating with PCB contamination.  A percentage of PCBs consumed or inhaled will migrate to the lining of the lungs and stay there due to their persistent nature.  Medical sources generally state that up to 90 percent of all lung cancers are caused by tobacco smoking, with only a small percentage due to environmental pollutants; however, numerous studies cited in this section describe a special role that PCBs may play in some lung cancers.

PCBs are well-known as stimulants or "inducers" of enzymes in several organs of the body, including the lungs. Studies show that these enzymes can convert other chemicals, such as tobacco smoke or common urban air pollutants, into carcinogens. In fact, PCBs are such good inducers that a commercial mixture of PCBs called Aroclor 1254 is used routinely by laboratories to induce enzymes in order to test the ability of other chemicals to cause mutations or cancer. Commercial labs currently sell pre-made enzyme mixtures induced by PCBs, for use in this medical research. (See In Vitro Technologies website.)

As a result, many scientists classify PCBs as "promoters" of cancer, provided the cancer has been started by another cause. In addition, PCBs may stimulate dormant cancers to become active and deadly at much earlier ages.

This combined toxicity effect would be difficult to sort out in an epidemiological study of humans with lung cancer in the real world. Toxicologists usually adjust statistics in PCB studies to rule out cancer cases from tobacco smoking or other known cancer risk factors, when, in fact, PCB enzyme induction might have contributed to some of these cancers.

Unfortunately, most people now assume that smokers who develop lung cancer are suffering from a self-inflicted illness, with no one else to blame but the tobacco companies who addicted them. It’s important to recognize that other corporate entities may be equally responsible, if lung cancers are stimulated by widespread PCB pollution. 

The High Cost of Lung Cancer

Lung cancer is the leading cancer killer in both men and women, locally and nationwide. According to the American Lung Association, there were an estimated 164,100 new cases of lung cancer and an estimated 156,900 deaths from lung cancer in the United States in 2000. 

In the past 40 years, women have experienced a 200 percent increase in mortality rates due to lung cancer, which has now surpassed breast cancer as the leading cause of cancer death among women. 

The National Cancer Institute estimates the overall annual costs for all cancers at $107 billion: $37 billion for all health expenditures, $11 billion for lost productivity due to illness and $59 billion for lost productivity due to premature death. Lung cancers are responsible for a significant portion of these costs, and PCBs may be factor.

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Summary of Human Studies of Lung Cancer and PCBs

The Human Studies

Upcoming Research

Summary of Animal Studies of Lung Cancer and PCBs

The Animal Studies 1 - 31

The Animal Studies 32 - 32

Upcoming Research

Studies Without Abstracts

Links to More Information

References