Cancer Risk Factors

A set genetic and environmental factors increase the risk of cancer.
One important is family history. Some families have a higher risk for certain cancers when compared with other families. For example, the risk for women suffering from breast cancer increased from 1.5 to 3 times if his mother or sister had breast cancer.

Some breast cancer associated with a specific genetic mutation, which was more frequent in some ethnic groups and families. Women with mutations in this gene have a chance of 80-90% for breast cancer and 40-50% for ovarian cancer. Researcher have found that 1% of Ashkenazi Jewish women have this gene mutation.

Other cancers that tend to be inherited in the family is skin cancer and colon cancer.

Chromosomal abnormalities increases the risk of cancer. For example, a person with Down Syndrome, which has a 3 pieces of chromosome 21, has a 12-30 times higher risk of developing acute leukemia.

A number of environmental factors increase the risk of cancer. One of the most important is cigarette smoking. Cigarette smoking increase the risk of lung cancer, mouth, larynx (vocal cord ) and the bladder.
Excessive exposure of ultraviolet light, particularly from sunlight, causing skin cancer.

Ionizing radiation ( which is carcinogenic ) is used in X-rays, generated from nuclear power plants and atomic bomb and can reach a great distance. For example, people who survived the atomic bomb dropped on Hiroshima and Nagasaki in World War II, has a high risk of occurrence of leukemia.

By uranium exposure in mine workers has been associated with the occurrence of lung cancer 10-20 years later, the higher the risk if the miners also smoked.

Long-term exposure to ionizing radiation affects a person to suffer blood cell cancers, including acute leukemia.

Food is another important risk factor for cancer, particularly cancers of the digestive tract. High-fiber diet reduces the likelihood of colon cancer. Diets that contain lots of smoked and pickled foods ( in the form of pickles ) increase the risk of gastric cancer. Reduce fat to less than 30% of total calories, would reduce the risk of colon cancer, breast, and prostate. Alcohol drinkers have a higher risk of esophageal cancer.

Many chemicals are know to cause cancer and many other chemical are suspected of causing cancer. Exposure to certain chemicals may increase the risk of cancer after a few years later. For example, exposure to asbestos can cause lung cancer and mesothelioma ( Pleural cancer ). These risks will be greater  if asbestos workers is also a cigarette smoker.

The risk of cancer also varies according to one's residence. The risk of colon and breast cancer in Japanese is low, but this risk is increased in Japan people living in America and in the end will have a risk as great as other America citizens. The Japanese have gastric cancer incidence rates are very high, but the Japanese people who were born in America this figure is lower. Geographic variation in cancer risk is presumably involves many factors, namely a combination of genetics, food and environment.

Some viruses cause cancer in humans and other viruses suspected of causing cancer. Papilloma virus that causes genital warts is one likely cause of cervical cancer in women. Cytomegalovirus causes Kaposi's sarcoma. Hepatitis B virus causes can cause liver cancer, although it is not know carcinogens or promoters. In Africa, Epstein-Barr virus causes Burkitt;s lymphoma, whereas in China these viruses cause cancer of the nose and throat. It was clear, that some additional factors ( environmental or genetic ), is required for the occurrence of cancer caused by Epstein-Barr virus. Some human retro virus, such as the HIV virus, causes lymphoma and other blood cancers.

Infection by the parasite Schistosoma ( Bilharzia ) could cause bladder cancer due to chronic irritation of the bladder. But other chronic irritants do not cause cancer. Infection by Clonorchis, which is mainly found in the Far East, can cause pancreatic cancer and biliary tract.



 

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