The causes and the risk of occurrence of Cancer

HOW THE OCCURRENCE OF CANCER

The causes and the risk of occurrence of Cancer

At this time the Article Postings will be discussed about the causes and risks of the occurrence of Cancer.

Cancer is a cell that has lost its normal controls and mechanisms, so as to experience an irregular growth.

Cancer can be terjdi from various tissues in various organs.

In line with the growth and perkembangbiakannya, cancer cells form a mass of malignant tissue that infiltrated the nearby tissue and can spread (metastasis) to the rest of the body.

Cancer cells are formed from normal cells in a process called a complicated transformation, which consists of the stages of initiation and promotion.

At the stage of initiation occurred a change in the genetic material of cells that become malignant cells fishing.

Changes in the genetic material of cells is caused by an agent called carcinogens, which can be chemicals, viruses, radiation (shines) or sunlight.

But not all cells have the same sensitivity to a carcinogen. Genetic abnormalities in cells or other materials called promoters cell, causing a more vulnerable to carcinogens. Even physical disorders menahunpun could make the cells become more sensitive to experience a malignancy.

At this stage of the campaign, a cell that has undergone the initiation will turn violent.

Cells that have not passed through the stage of initiation will not be affected by the promotion. Because it takes several factors for the occurrence of malignancy (a combination of the sensitive cells and a carcinogen).

In a process by which a normal cell into a malignant cells, ultimately DNA from these cells will undergo changes.

Changes in the genetic material of cells is often difficult to find, but the occurrence of cancer can sometimes be known from the existence of a change in the size or shape of a particular chromosome.

For example, an abnormal chromosome called the Philadelphia chromosome found in about 80% of sufferers of chronic mielositik leukemia.

Genetic changes have also been found in brain tumors and cancer of the colon, breast, lung and bone.

It may take a series of changes of chromosomes to the onset of cancer.

Research on familial nasal polyposis of the colon (intestinal disorders are hereditary in the form of the growth of polyps that turn into malignant), has brought us to a conjecture how this happened to colon cancer.

A normal colon lining starts growing actively (hiperproliferasi), because their cells no longer have a gene suppressor on chromosome 5 that under normal circumstances the layer growth control.

Further changes in the DNA that light ease formation of adenoma (benign tumor).

The other gene (oncogene RAS) causes the adenoma grows more active.

The loss of a gene suppressor on chromosome 18 will further stimulate the adenoma and ultimately loss of genes on chromosome 17 is a benign adenoma will change into cancer.

Other additional changes could cause widespread cancer throughout the body (metastases have).

At the time of a cell to become malignant, the immune system can often ruin it before the malignant cells to compound and become a cancer.

Cancer tends to occur if the immune system doesn't function normally, as happened in sufferers. AIDS, people who use drugs and immune suppressant in certain autoimmune diseases.

But the immune system is not always effective, cancer can penetrate this protection even though the immune system functioning normally.

Carcinogens: Chemicals That Could Cause Cancer

CANCER RISK FACTORS

A group of genetic and environmental factors increase the risk of the occurrence of cancer.

One of the important thing is family history.

Some families have a higher risk for suffering from certain cancers when compared with other families.

For example the risk of women suffering from breast cancer increases 1.5 to 3 times if his mother or sister had breast cancer.

Some breast cancer associated with a genetic mutation, which is more often found in some ethnic groups and families.

Women with gene mutation has a chance of 80-90% to suffer from breast cancer and 40-50% for suffering cancer of the ovaries.

Researchers have found that 1% of Ashkenazi Jewish women have this gene mutation.

Other cancers that tend to be passed down in families is skin cancer and colon cancer.

Chromosome abnormalities increases the risk of the occurrence of cancer.

For example, a person with Down's syndrome, which has 3 pieces of chromosome 21, have risk of 12-20 times higher for suffering from acute leukemia.

A number of environmental factors increase the risk of the occurrence of cancer.

The most important one of which is smoking sigaret. Cigarette smoking increases the risk of occurrence of sigaret cancer of the lung, mouth, larynx (vocal cords) and bladder.

Excessive exposure to ultraviolet rays, especially from sunlight, causing skin cancer.

Ionizing radiation (which is a carcinogenic) is used in x-rays, generated from a nuclear power plant and the explosion of the atomic bomb and could reach a great distance.

For example, survivors of the atomic bombs dropped on Hiroshima and Nagasaki in World War II, are at high risk against the onset of leukemia.

Exposure by uranium on miners has been associated with the occurrence of lung cancer 10-20 years later, the higher your risk if the miners are also smoked.

Long-term exposure to ionizing radiation influence against a person to suffer from cancer of blood cells, including acute leukemia.

Food is another important risk factor for cancer, especially cancer of the digestive tract.

High fiber diet reduces the likelihood of the occurrence of colon cancer.

Diets that contain foods that are pickled and smoked (in the form of pickles) increases the risk of occurrence of gastric cancer.

Reduce fat to less than 30% of total calories, will reduce the risk of the occurrence of cancer of the colon, breast and protat.

Alcohol drinkers have higher risk against the occurrence of cancer of the esophagus.

Many chemicals are known to cause cancer and other chemicals that are suspected as the cause of many cancers.

Exposure to certain chemicals may increase the risk of the occurrence of cancer after several years later.

For example, exposure to asbestos can cause lung cancer and mesotelioma (cancer of the pleura).

This risk will be greater if asbestos workers was also a smoker sigaret.

The risk of occurrence of cancer also varies based on the place of residence of the person.

The risk of the occurrence of cancer of the colon and breast in Japan is low, but the risk is increased in people who live in Japan and America will eventually have the same magnitude of risk with other American residents.

The people of Japan has the incidence of gastric cancer are very high; but in Japan people born in America this figure is lower.

Geographical variation in cancer risk it presumably involves many factors, i.e. a combination of genetic, environmental and food.

Some viruses cause cancer in humans and other viruses is suspected as a cause of cancer.

Papilloma virus that causes warts genitalis presumably is one cause of cervical cancer in women.

Sitomegalo virus causes Kaposi's Sarcoma.

Virus hepatitis B can cause liver cancer, although the carcinogens or promotornya is not known.

In Africa, the Epstein-Barr virus causes Burkitt Lymphoma, while in China the virus is causing cancer of the nose and throat. Clearly, that some additional factors (genetic or environmental), necessary for the occurrence of cancer caused by the Epstein-Barr virus.

Some retro virus human, such as the HIV virus, causing the lymphoma and other blood cancers.

Infection by the parasite Schistosoma (Bilharzia) could cause bladder cancer due to the occurrence of chronical irritation in the bladder. But the cause of the irritation of other chronical does not cause cancer.

Clonorchis infection by, which is found primarily in the far East, can lead to cancer of the pancreas and bile duct.

CANCER EPIDEMIOLOGY

Cancer risk has changed. Cancer was once commonly found now are rare.

For example in the 1930s of gastric cancer in the U.S. is 4 times more commonly found than it is now. Perhaps this is because fewer people now consume foods that are smoked or pickled.

Meanwhile the number of occurrence of lung cancer in the U.S. in 1930 was 5 of every 100,000 people increased to 114 from every 100,000 in 1990, and this incident figures soared in women. This change was almost certainly the result of the increasing usage of smoking sigaret. Smoking also causes increased sigaret oral cancer.

Age is an important factor in the onset of cancer.

Some cancers, such as Wilms tumor, leukemia Acute Lymphocytic lymphoma and Burkitt, a lot of attacking a young age. Why this happens is still not fully understood, but one of the factors at play is a genetic predisposition.

But most cancers occur in old age.

Cancer of the prostate, stomach and large intestine, most likely to occur after the age of 60 years.

In the U.S., more than 60% of cancers in people with undiagnosed who are aged above 65 years.

Overall, the risk of the occurrence of cancer in the U.S. increased 2 times every 5 years after the age of 25 years.

Increasing the risk of cancer may be the combination of the increasing length of time and increase exposure to carcinogens and the weakening of the immune system.