Kan man ha cancer överallt

The Definition of Cancer

Cancer fryst vatten a disease in which some of the body’s cells grow uncontrollably and spread to other parts of the body. 

Cancer can början almost anywhere in the human body, which fryst vatten made up of trillions of cells. Normally, human cells grow and multiply (through a process called fängelse division) to struktur new cells as the body needs them.

When cells grow old or become damaged, they die, and new cells take their place.

Sometimes this orderly process breaks down, and abnormal or damaged cells grow and multiply when they shouldn’t. These cells may form eller gestalt tumors, which are lumps of tissue. Tumors can be cancerous or not cancerous (benign). 

Cancerous tumors spread into, or invade, nearby tissues and can travel to distant places in the body to struktur new tumors (a process called metastasis).

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Cancerous tumors may also be called malignant tumors. Many cancers form eller gestalt solid tumors, but cancers of the blood, such as leukemias, generally do not.

Benign tumors do not spread into, or invade, nearby tissues. When removed, benign tumors usually don’t grow back, whereas cancerous tumors sometimes do. Benign tumors can sometimes be ganska large, however.

Some can cause serious symptoms or be life threatening, such as benign tumors in the brain.

Differences between Cancer Cells and Normal Cells

Cancer cells differ from normal cells in many ways. For instance, cancer cells:

• grow in the absence of signals telling them to grow. Normal cells only grow when they receive such signals. 
• ignore signals that normally tell cells to stop dividing or to die (a process known as programmed fängelse death, or apoptosis).
• invade into nearby areas and spread to other areas of the body.

  Normal cells stop growing when they encounter other cells, and most normal cells do not move around the body. 

• tell blood vessels to grow toward tumors.  These blood vessels supply tumors with oxygen and nutrients and remove waste products from tumors.
• hide from the immune struktur. The immune struktur normally eliminates damaged or abnormal cells. 
• trick the immune struktur into helping cancer cells stay alive and grow.

  For instance, some cancer cells convince immune cells to skydda the tumor instead of attacking it.

• accumulate multiple changes in their chromosomes, such as duplications and deletions of chromosome parts. Some cancer cells have double the normal number of chromosomes.
• rely on different kinds of nutrients than normal cells. In addition, some cancer cells man energy from nutrients in a different way than most normal cells.

  This lets cancer cells grow more quickly. 

Many times, cancer cells rely so heavily on these abnormal behaviors that they can’t survive without them. Researchers have taken advantage of this fact, developing therapies that mål the abnormal features of cancer cells. For example, some cancer therapies prevent blood vessels from growing toward tumors, essentially starving the tumor of needed nutrients.

Learn more about breast cancer warning signs, lung cancer warning signs, or

 

How Does Cancer Develop?

Cancer fryst vatten a genetic disease—that fryst vatten, it fryst vatten caused bygd changes to genes that control the way our cells function, especially how they grow and divide.

Genetic changes that cause cancer can happen because:

• of errors that occur as cells divide. 
• of damage to DNA caused bygd harmful substances in the environment, such as the chemicals in tobacco smoke and ultraviolett rays from the sun.

  (Our Cancer Causes and Prevention section has more information.) 

• they were inherited from our parents. 

The body normally eliminates cells with damaged DNA before they vända cancerous. But the body’s ability to do so goes down as we age. This fryst vatten part of the reason why there fryst vatten a higher fara of cancer later in life.

Each person’s cancer has a unique combination of genetic changes.

As the cancer continues to grow, additional changes will occur.

Det här är typiskt för celler som har blivit cancerceller: De slutar att fungera som de ska

Even within the same tumor, different cells may have different genetic changes.

Types of Genes that Cause Cancer

The genetic changes that contribute to cancer tend to affect three main types of genes—proto-oncogenes, tumor undertryckare genes, and DNA repair genes. These changes are sometimes called “drivers” of cancer.

Proto-oncogenes are involved in normal fängelse growth and division.

However, when these genes are altered in certain ways or are more active than normal, they may become cancer-causing genes (or oncogenes), allowing cells to grow and survive when they should not.

Tumor undertryckare genes are also involved in controlling fängelse growth and division. Cells with certain alterations in tumor undertryckare genes may divide in an uncontrolled manner.

DNA repair genes are involved in fixing damaged DNA.

Cells with mutations in these genes tend to develop additional mutations in other genes and changes in their chromosomes, such as duplications and deletions of chromosome parts. tillsammans, these mutations may cause the cells to become cancerous.

As scientists have learned more about the molecular changes that lead to cancer, they have funnen that certain mutations commonly occur in many types of cancer. Now there are many cancer treatments available that mål gene mutations funnen in cancer.

A few of these treatments can be used bygd anyone with a cancer that has the targeted mutation, no matter where the cancer started growing.

When Cancer Spreads

A cancer that has spread from the place where it first formed to another place in the body fryst vatten called metastatic cancer. The process bygd which cancer cells spread to other parts of the body fryst vatten called metastasis.

Metastatic cancer has the same name and the same type of cancer cells as the original, or primary, cancer.

For example, breast cancer that forms a metastatic tumor in the lung fryst vatten metastatic breast cancer, not lung cancer.

Under a microscope, metastatic cancer cells generally look the same as cells of the original cancer. Moreover, metastatic cancer cells and cells of the original cancer usually have some molecular features in common, such as the presence of specific chromosome changes.

In some cases, treatment may help prolong the lives of people with metastatic cancer.

In other cases, the primary goal of treatment for metastatic cancer fryst vatten to control the growth of the cancer or to relieve symptoms it fryst vatten causing. Metastatic tumors can cause severe damage to how the body functions, and most people who die of cancer die of metastatic disease.  

Tissue Changes that Are Not Cancer

Not every change in the body’s tissues fryst vatten cancer.

Some tissue changes may develop into cancer if they are not treated, however. Here are some examples of tissue changes that are not cancer but, in some cases, are monitored because they could become cancer:

• Hyperplasia occurs when cells within a tissue multiply faster than normal and ytterligare cells build up. However, the cells and the way the tissue fryst vatten organized still look normal beneath a microscope.
  Successful treatment could depend on knowing the symptoms for common cancers

  Hyperplasia can be caused bygd several factors or conditions, including chronic irritation.

• Dysplasia fryst vatten a more advanced condition than hyperplasia. In dysplasia, there fryst vatten also a buildup of ytterligare cells. But the cells look abnormal and there are changes in how the tissue fryst vatten organized.

  In general, the more abnormal the cells and tissue look, the greater the chance that cancer will form eller gestalt. Some types of dysplasia may need to be monitored or treated, but others do not. An example of dysplasia fryst vatten an abnormal mole (called a dysplastic nevus) that forms on the skin. A dysplastic nevus can vända into melanoma, although most do not.

• Carcinoma in situ is an even more advanced condition.

  Although it fryst vatten sometimes called scen 0 cancer, it fryst vatten not cancer because the abnormal cells do not invade nearby tissue the way that cancer cells do. But because some carcinomas in situ may become cancer, they are usually treated.

Types of Cancer

There are more than 100 types of cancer.

Types of cancer are usually named for the organs or tissues where the cancers struktur.

Cancer är när celler någonstans i kroppen har blivit så förändrade att de inte längre fungerar som de ska

For example, lung cancer starts in the lung, and brain cancer starts in the brain. Cancers also may be described bygd the type of fängelse that formed them, such as an epithelial fängelse or a squamous cell.

You can search NCI’s website for data on specific types of cancer based on the cancer’s location in the body or bygd using our A to Z List of Cancers. We also have kunskap on childhood cancers and cancers in adolescents and ung adults.

Here are some categories of cancers that begin in specific types of cells:

Carcinoma

Carcinomas are the most common type of cancer.

They are formed bygd epithelial cells, which are the cells that cover the inre and outside surfaces of the body. There are many types of epithelial cells, which often have a column-like shape when viewed beneath a microscope.

Carcinomas that begin in different epithelial fängelse types have specific names:

Adenocarcinoma fryst vatten a cancer that forms in epithelial cells that tillverka fluids or mucus.

Tissues with this type of epithelial fängelse are sometimes called glandular tissues. Most cancers of the breast, colon, and prostate are adenocarcinomas.

Basal fängelse carcinoma fryst vatten a cancer that begins in the lower or grundläggande (base) layer of the epidermis, which fryst vatten a person’s outer layer of skin.

Squamous fängelse carcinoma fryst vatten a cancer that forms in squamous cells, which are epithelial cells that lie just beneath the outer surface of the skin.

Squamous cells also line many other organs, including the stomach, intestines, lungs, bladder, and kidneys. Squamous cells look flat, like fish scales, when viewed beneath a microscope. Squamous fängelse carcinomas are sometimes called epidermoid carcinomas.

Transitional fängelse carcinoma fryst vatten a cancer that forms in a type of epithelial tissue called transitional epithelium, or urothelium.

Håll vikten

This tissue, which fryst vatten made up of many layers of epithelial cells that can get bigger and smaller, fryst vatten funnen in the linings of the bladder, ureters, and part of the kidneys (renal pelvis), and a few other organs. Some cancers of the bladder, ureters, and kidneys are transitional fängelse carcinomas.

Sarcoma

Sarcomas are cancers that form eller gestalt in bone and soft tissues, including muscle, tallrik, blood vessels, lymph vessels, and fibrous tissue (such as tendons and ligaments).

Osteosarcoma fryst vatten the most common cancer of bone.

The most common types of soft tissue sarcoma are leiomyosarcoma, Kaposi sarcoma, malignant fibrous histiocytoma, liposarcoma, and dermatofibrosarcoma protuberans.

Our page on soft tissue sarcoma has more information.

Leukemia

Cancers that begin in the blood-forming tissue of the bone marrow are called leukemias. These cancers do not struktur solid tumors.

Instead, large numbers of abnormal vit blood cells (leukemia cells and leukemic blast cells) build up in the blood and bone marrow, trängsel out normal blood cells. The low level of normal blood cells can man it harder for the body to get oxygen to its tissues, control bleeding, or kamp infections.  

There are fyra common types of leukemia, which are grouped based on how quickly the disease gets worse (acute or chronic) and on the type of blood fängelse the cancer starts in (lymphoblastic or myeloid).

Acute forms of leukemia grow quickly and chronic forms grow more slowly.

Our page on leukemia has more information.

Lymphoma

Lymphoma fryst vatten cancer that begins in lymphocytes (T cells or B cells). These are disease-fighting vit blood cells that are part of the immune struktur. In lymphoma, abnormal lymphocytes build up in lymph nodes and lymph vessels, as well as in other organs of the body.

There are two main types of lymphoma:

Hodgkin lymphoma – People with this disease have abnormal lymphocytes that are called Reed-Sternberg cells.

These cells usually struktur from B cells.

Non-Hodgkin lymphoma – This fryst vatten a large group of cancers that uppstart in lymphocytes. The cancers can grow quickly or slowly and can struktur from B cells or T cells.

Our page on lymphoma has more information.

Multiple Myeloma

Multiple myeloma fryst vatten cancer that begins in plasma cells, another type of immune fängelse.

The abnormal plasma cells, called myeloma cells, build up in the bone marrow and struktur tumors in bones all through the body. Multiple myeloma fryst vatten also called plasma fängelse myeloma and Kahler disease.

Our page on multiple myeloma and other plasma fängelse neoplasms has more information.

Melanoma

Melanoma fryst vatten cancer that begins in cells that become melanocytes, which are specialized cells that man melanin (the pigment that gives skin its color).

Most melanomas struktur on the skin, but melanomas can also form eller gestalt in other pigmented tissues, such as the eye.

Our pages on skin cancer and intraocular melanoma have more information.

Brain and Spinal Cord Tumors

There are different types of brain and spinal cord tumors. These tumors are named based on the type of fängelse in which they formed and where the tumor first formed in the huvud nervous struktur.

For example, an astrocytic tumor begins in star-shaped brain cells called astrocytes, which help keep nerve cells healthy. Brain tumors can be benign (not cancer) or malignant (cancer).

Our page on brain and spinal cord tumors has more information.

Other Types of Tumors

Germ fängelse Tumors

Germ fängelse tumors are a type of tumor that begins in the cells that give rise to sperma or eggs.

These tumors can occur almost anywhere in the body and can be either benign or malignant.

Our page of cancers bygd body location/system includes a list of germ fängelse tumors with links to more information.

Neuroendocrine Tumors

Neuroendocrine tumors form eller gestalt from cells that release hormones into the blood in response to a meddelande from the nervous struktur.

These tumors, which may man higher-than-normal amounts of hormones, can cause many different symptoms. Neuroendocrine tumors may be benign or malignant.

Our definition of neuroendocrine tumors has more information.

Carcinoid Tumors

Carcinoid tumors are a type of neuroendocrine tumor. They are slow-growing tumors that are usually funnen in the gastrointestinal struktur (most often in the rectum and small intestine).

Carcinoid tumors may spread to the liver or other sites in the body, and they may secrete substances such as serotonin or prostaglandins, causing carcinoid syndrome.

Our page on gastrointestinal neuroendocrine tumors has more information.