Origin of Cancer
Cancer is a condition in which cells have lost normal control mechanisms, so that experienced abnormal growth, rapid and uncontrolled. Cancer cells will continue dividing, and ignores the rule of laws of breeding. Cancer can occur from various tissues in various organs, such as skin cells, liver cells, blood cells, brain cells, stomach cells, intestinal cells, lung cells, urinary tract cells, and various other body cells. In line with the growth and breeding, cancer cells form a mass of malignant tissue that infiltrate into nearby tissue (invasive) and can spread (metastasize) throughout the body. Cancer cells are formed from normal cells in a complex process called transformation, which consists of initiation and promotion stage.
At the initiation stage occurs a change in the genetic material of cells that provoke the cells become malignant. Changes in the cell's genetic material is caused by an agency called carcinogens, which can include chemicals, viruses, radiation (irradiation) or sunlight. But not all cells have the same sensitivity to a carcinogen. Genetic abnormalities in cells or other material which is called the promoter, causing the cells more susceptible to a carcinogen. Even the physical disruption menahunpun can make cells become more sensitive to having a malignancy.
At the stage of promotion, a cell that has undergone initiation will become malignant.
cells that have not passed the stage of initiation is not affected by the campaign. because it takes several factors for the occurrence of malignancies (combination of a sensitive cell and a carcinogen).
When a cell becomes malignant, the immune system can often spoil before these malignant cells multiply and become a cancer. However, if the immune system is not functioning normally, the body vulnerable to cancer risk, as happens in AIDS patients, people who use immune-suppressing drugs and in certain autoimmune diseases. But the immune system was not always effective, so that cancers are sometimes still able to penetrate this protection even if the immune system to function normally.
In almost all types of cancer, the success rate of therapy was associated with stage at diagnosis and treatment. The higher the stage at diagnosis, the success of therapy could decrease with a more aggressive treatment modalities.
Cancer Risk Factors
It is known that a set of genetic and environmental factors may increase the risk of cancer. Factors that may increase the risk include:
1. Family History
Family history is one of the most important factor to remember cancer can be influenced by genetic disorders. Some families may have higher risk of certain cancers when compared with other families, such as women's risk for 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, such as found in 1% of Ashkenazi women. Other cancers that tend to be inherited in the family is skin cancer and colon cancer.
2. Chromosome Abnormalities
For example, a person with Down syndrome, which has a 3 pieces of chromosome 21, has a 12-20 times higher risk of developing acute leukemia.
3. Environmental Factors
A number of environmental factors can increase the risk of cancer, one of the most important thing is smoking. Smoking increases the risk of lung cancer, mouth, larynx (vocal cords) and the bladder.
Other environmental factors such as excessive exposure of ultraviolet light, particularly from sunlight, causing skin cancer.
In addition, r adiasi ionization (which is carcinogenic) used in x-rays, generated from nuclear power plants and atomic bombs and can reach very long distances, can also increase the risk of cancer. 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. Uranium exposure in mine workers also increase the risk of lung cancer 10-20 years later, and this risk will be higher if the miners also smoked.
4. Food
Food is another important risk factor for cancer, particularly cancers of the digestive tract. For example, eating foods that contain lots of smoked and pickled foods (in the form of pickles) can increase the risk of gastric cancer. Alcohol drinkers also had a higher risk of esophageal cancer.
If someone is eating foods that are high in fiber, it can reduce the likelihood of colon cancer. Reduce fat to less than 30% of total calories, would reduce the risk of colon cancer, breast and protat.
5. Chemicals
Many chemicals are known to cause cancer and many others are suspected of causing cancer. Exposure to certain chemicals may increase the risk of cancer after a few years later, such as exposure to asbestos can cause lung cancer and mesotheliomas (pleural cancer), and skin cancer are found in paint workers and workers who clean chimneys because of the content of hydrocarbon compounds .
6. Residence
The risk of cancer also varies according to one's residence. For example, the risk of colon and breast cancer in Japan is low, but this risk is increased in Japanese people living in America and in the end will have a risk as great as other American citizens. Uniquely, 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.
7. Virus
Some viruses are known to cause cancer in humans and other viruses suspected of causing cancer. Cancer-causing virus is also called oncogenic viruses. For example, papilloma virus that causes genital warts is one likely cause of cervical cancer in women, cytomegalovirus causes Kaposi's sarcoma, hepatitis B virus and hepatitis C can cause liver cancer, carcinogens or promoters although it is not known.
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, can cause lymphoma and other blood cancers.
8. Infection
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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