Carcinogens are substances that can cause or increase the risk of developing cancer. Below are a few examples of well-known carcinogens:
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Smoking
- In addition to lung cancer, tobacco consumption causes cancer of the larynx, pancreas, kidney, bladder in addition to other cancers.
- Smoking in conjunction with alcohol drinking leads to a higher risk of cancer of the oral cavity and the esophagus.
- In most developed countries, tobacco accounts for as much as 30% of all malignant tumors.
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Heavy alcohol drinking
- Drinking too much alcohol consistently over a long period of time can cause cancer of the oral cavity, pharynx, larynx, esophagus, and liver, and may increase the risk of breast and colorectal cancers.
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Pollution
- Environmental factors such as pollution of air, water or soil is estimated to account for 1-4% of cancers.
- Indoor carcinogens include tobacco smoke.
- High levels of arsenic and chlorination byproducts in some countries reach dangerous levels that may be associated with cancer.
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Chronic infections
- Hepatitis B infection is associated with liver cancer.
- The human papillomavirus (HPV) is associated with cancer of the cervix and uterus.
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Radiation
- Exposure to high-levels of radiation alters cell activity, which can lead to cancer.
- Sunlight contains ultraviolet (UV) radiation, which can lead to skin cancer if people are exposed to it too much, especially if it causes bad sunburns.