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Páginas: 7 (1625 palabras)
Publicado: 25 de septiembre de 2012
What Is Cancer?
Cancer is the general name for a group of more than 100 diseases. Although there are many kinds of cancer, all cancers start because abnormal cells grow out of control. Untreated cancers can cause serious illness and death.
Normal cells in the body
The body is made up of trillions of living cells. Normal body cells grow, divide, and die in an orderly fashion. During theearly years of a person’s life, normal cells divide faster to allow the person to grow. After the person becomes an adult, most cells divide only to replace worn-out or dying cells or to repair injuries.
How cancer starts
Cancer starts when cells in a part of the body start to grow out of control. Cancer cell growth is different from normal cell growth. Instead of dying, cancer cellscontinue to grow and form new, abnormal cells. Cancer cells can also invade (grow into) other tissues, something that normal cells cannot do. Growing out of control and invading other tissues are what makes a cell a cancer cell.
Cells become cancer cells because of DNA (deoxyribonucleic acid) damage. DNA is in every cell and it directs all the cell’s actions. In a normal cell, when DNA gets damagedthe cell either repairs the damage or the cell dies. In cancer cells, the damaged DNA is not repaired, and the cell doesn’t die like it should. Instead, the cell goes on making new cells that the body doesn’t need. These new cells all have the same abnormal DNA as the first cell does.
People can inherit abnormal DNA, but most DNA damage is caused by mistakes that happen while the normal cell isreproducing or by something in the environment. Sometimes the cause of the DNA damage may be something obvious like cigarette smoking or sun exposure. But it’s rare to know exactly what caused any one person’s cancer.
In most cases, the cancer cells form a tumor. Some cancers, like leukemia, rarely form tumors. Instead, these cancer cells involve the blood and blood-forming organs and circulatethrough other tissues where they grow.
What Causes Cancer?
Cancer is a complex group of diseases with many possible causes. In this section you can learn more about the known causes of cancer, including genetic factors; lifestyle factors such as tobacco use, diet, and physical activity; certain types of infections; and environmental exposures to different types of chemicals andradiation.
GENETICS AND CANCER
Some types of cancer run in certain families, but most cancers are not clearly linked to the genes we inherit from our parents. In this section you can learn more about the complex links between genes and cancer, as well as genetic testing and how it is used.
READ MORE »
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TOBACCO AND CANCER
In this section you can get information oncigarette, cigar, and smokeless tobacco use, and learn how it affects different groups of people.
READ MORE »
[pic]
DIET AND PHYSICAL ACTIVITY
Get the facts on how diet, physical activity, excess body weight, and alcohol use may affect your risk of cancer.
READ MORE »
[pic]
SUN AND UV EXPOSURE
In this section you can learn more about the link between too much sun exposureand cancer.
READ MORE »
[pic]
OTHER CARCINOGENS
Learn about some of the environmental causes of cancer that may lurk in our homes, at work, in pollution, and even in some medical tests and treatments. You can also learn how some types of infections are linked to cancer.
READ MORE »
Breast cancer
• Yearly mammograms are recommended starting at age 40 and continuing for aslong as a woman is in good health
• Clinical breast exam (CBE) about every 3 years for women in their 20s and 30s and every year for women 40 and over
• Women should know how their breasts normally look and feel and report any breast change promptly to their health care provider. Breast self-exam (BSE) is an option for women starting in their 20s.
Some women – because of their family...
Cancer is the general name for a group of more than 100 diseases. Although there are many kinds of cancer, all cancers start because abnormal cells grow out of control. Untreated cancers can cause serious illness and death.
Normal cells in the body
The body is made up of trillions of living cells. Normal body cells grow, divide, and die in an orderly fashion. During theearly years of a person’s life, normal cells divide faster to allow the person to grow. After the person becomes an adult, most cells divide only to replace worn-out or dying cells or to repair injuries.
How cancer starts
Cancer starts when cells in a part of the body start to grow out of control. Cancer cell growth is different from normal cell growth. Instead of dying, cancer cellscontinue to grow and form new, abnormal cells. Cancer cells can also invade (grow into) other tissues, something that normal cells cannot do. Growing out of control and invading other tissues are what makes a cell a cancer cell.
Cells become cancer cells because of DNA (deoxyribonucleic acid) damage. DNA is in every cell and it directs all the cell’s actions. In a normal cell, when DNA gets damagedthe cell either repairs the damage or the cell dies. In cancer cells, the damaged DNA is not repaired, and the cell doesn’t die like it should. Instead, the cell goes on making new cells that the body doesn’t need. These new cells all have the same abnormal DNA as the first cell does.
People can inherit abnormal DNA, but most DNA damage is caused by mistakes that happen while the normal cell isreproducing or by something in the environment. Sometimes the cause of the DNA damage may be something obvious like cigarette smoking or sun exposure. But it’s rare to know exactly what caused any one person’s cancer.
In most cases, the cancer cells form a tumor. Some cancers, like leukemia, rarely form tumors. Instead, these cancer cells involve the blood and blood-forming organs and circulatethrough other tissues where they grow.
What Causes Cancer?
Cancer is a complex group of diseases with many possible causes. In this section you can learn more about the known causes of cancer, including genetic factors; lifestyle factors such as tobacco use, diet, and physical activity; certain types of infections; and environmental exposures to different types of chemicals andradiation.
GENETICS AND CANCER
Some types of cancer run in certain families, but most cancers are not clearly linked to the genes we inherit from our parents. In this section you can learn more about the complex links between genes and cancer, as well as genetic testing and how it is used.
READ MORE »
[pic]
TOBACCO AND CANCER
In this section you can get information oncigarette, cigar, and smokeless tobacco use, and learn how it affects different groups of people.
READ MORE »
[pic]
DIET AND PHYSICAL ACTIVITY
Get the facts on how diet, physical activity, excess body weight, and alcohol use may affect your risk of cancer.
READ MORE »
[pic]
SUN AND UV EXPOSURE
In this section you can learn more about the link between too much sun exposureand cancer.
READ MORE »
[pic]
OTHER CARCINOGENS
Learn about some of the environmental causes of cancer that may lurk in our homes, at work, in pollution, and even in some medical tests and treatments. You can also learn how some types of infections are linked to cancer.
READ MORE »
Breast cancer
• Yearly mammograms are recommended starting at age 40 and continuing for aslong as a woman is in good health
• Clinical breast exam (CBE) about every 3 years for women in their 20s and 30s and every year for women 40 and over
• Women should know how their breasts normally look and feel and report any breast change promptly to their health care provider. Breast self-exam (BSE) is an option for women starting in their 20s.
Some women – because of their family...
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