What Is Cancer

What is cancer?

• A Collection of Related Diseases
• Difference between cancer cells and normal cells
• How does cancer rise
• "Drivers" of Cancer
• When cancer spreads
• Tissue changes are not cancerous
• Types of cancer

A Collection of Related Diseases

A divided lung cancer cell. Credit: National Institutes of Health

Cancer is a collection of name related diseases. In all types of cancers, some body cells have to be
split without any stops and spread in surrounding tissues.

Cancer can start almost anywhere in the human body, which is made up of trillion cells. Generally, human cells grow and divide the body in the form of new cells because they need the body. When cells become larger or damaged, then they die, and new cells take their place.

When cancer develops, however, this systematic process breaks down as more and more abnormal, old or damaged cells survive when they die, and when new cells are not needed, then they survive. . These extra cells can be divided without stopping and tumors are called growth.

Many cancers produce solid tumors, which are the mass of tissue, blood cancer, such as leukemia, generally does not make solid tumors

Cancer tumors are fatal, which means they can spread or invade nearby tissues. In addition to this, as well as increasing the tumor, some cancer cells can travel away from the blood or through the lymphatic system and make new tumors from the original tumor.

Unlike malignant tumors, benign tumors do not spread or invade nearby tissues. The benign tumor can sometimes be quite large, although when removed, they usually do not return, while malignant tumors sometimes occur, unlike most benign tumors in the body, benign brain tumor can threaten life. .

Difference between cancer cells and normal cells

Cancer cells are different from normal cells in many ways, allowing them to get out of control and become aggressive. One important difference is that cancer cells are less specific than normal cells. That is, while normal cells mature into very different cell types with specific functions, there are no cancer cells. This is one reason that unlike normal cells, cancer cells continue to be distributed without restriction.

In addition, cancer cells can ignore signals, which usually say to stop dividing the cells or to initiate a process called cell death, or epoxy disease, which is used to get rid of unnecessary cells in the body. Does.

Cancer cells may be able to affect normal cells, molecules and blood vessels, which spread around a tumor - an area known as micrometment. For example, cancer cells can stimulate surrounding normal cells to form blood vessels supplying tumors with oxygen and nutrients, which they need to grow. These blood vessels also remove waste products from the tumor.

Cancer cells are often able to avoid the immune system, a network of organs, tissues and special cells that protect the body from infection and other conditions. Although the immune system usually removes damaged or abnormal cells, some cancers can "hide" the immune system.

Tumors can also use the immune system to survive and grow. For example, with the help of some immune system cells, which usually prevent the runaway immune response, cancer cells can actually prevent the immune system from killing cancer cells.

How does cancer rise

Cancer is a genetic disease - that is, it is due to the change in the genes that control the way our cells, especially how they grow and split

Genetic changes due to cancer can be inherited from our parents. They can arise as a result of errors occurring during the life of a person, such as the cells are divided or damaging the DNA due to some environmental risks. Due to cancer, there are substances in environmental risks, such as chemicals in tobacco smoke, and radiation, such as ultraviolet rays (our cancer cause and more information in the Risk Factors page).

Each person has a unique combination of genetic changes in cancer. As the cancer progresses, additional changes will occur. Even within the same tumor, different cells may have different genetic changes

In general, compared to normal cells, cancer cells have more genetic changes such as mutation in DNA. Some of these changes have nothing to do with cancer; They may be the result of cancer, compared to the reason.

"Drivers" of Cancer

Genetic mutations that contribute to cancer affect the three major types of gene-proto-oncogen, tumor suppressor genes, and DNA repair genes. These changes are sometimes called "drivers" of cancer.

Proto-Oncogen are included in normal cell development and division. However, when these genes change in some way or become more active than normal, they can become cancerous (or oncogen) genes, allowing cells to grow and survive, when they do not want them .

Tumor suppressor gene is also involved in controlling cell growth and division. Cells can be divided in an arbitrary manner with some changes in the tumor suppressor gene.

DNA repair genes are included in fixing damaged DNA. In these genes, additional mutations develop in the other genes for mutation cells. Together, these mutations can cause cells to be cancerous.

As scientists have learned more about molecular changes that cause cancer, they have found that some changes are generally in many types of cancer. Because of this, cancer is sometimes seen as the type of genetic changes that they are considered to drive, not where they develop in the body and what cancer cells look like under the microscope.

When cancer spreads

In metastasis, they are removed from cancer cells from where they form first (primary cancer), travel through the blood or lymphatic system, and make new tumors (metastatic tumors) in other parts of the body. Metastatic tumor is the only type of cancer that is the primary tumor.

A cancer that has spread from the place where it has been started at some other place in the body, it is called metastatic cancer. The process through which cancer cells are spread to other parts of the body is called metastasis.

The name of metastatic cancer is the same and similar types of cancer cells are in the form of basic, or primary, cancer. For example, breast cancer spreads in the lungs and creates a metastatic tumor which is metastatic breast cancer, is not lung cancer.

Under the microscope, metastatic cancer cells generally look similar to the cells of the original cancer. In addition, metastatic cancer cells and mice in the primary cancer cells usually have some molecular properties, such as the presence of specific chromosomal changes.

Treatment can help to increase the life of some people with metastatic cancer. In general, however, the primary goal of treatment of metastatic cancer is to control the growth of cancer or to remove symptoms due to it. How can metastatic tumors severe damage to the body's functions, and most people die of cancer die of metastatic disease.

Tissue changes are not cancerous

Every change in body tissues is not cancerous. Some tissue changes can develop in the cancer if they are not treated, although there are some examples of tissue that are not cancerous, but in some cases, it is monitored:

Hyperplasia occurs when cells are formed more or less than normal and divide cells within a tissue, or are born. However, cells under a microscope and the way tissue is organized is normal. Hyperplasia can be due to many factors or conditions, including chronic irritation.

Dysplasia is a more serious condition than hyperplasia, there is also a creation of additional cells. But the cells look abnormal and how tissues are organized, there are some changes in it. In general, there are more abnormal cells and tissues, there will be more chance of cancer.

Some types of dysplasia may require monitors or treatment. An example of dysplasia is an abnormal sesame (called displastic nevus) that is made on the skin. Displastic nevus can change in melanoma, although most do not.

An even more serious condition is carcinoma in situ. Although this is sometimes called cancer, the brain does not have cancer, because abnormal cells do not spread beyond the original tissue. That is, the way they do not attack cancerous cells on nearby tissues, but because some casino can be cancerous, they are usually treated.

Normal cells can be cancerous cells Before cancerous cells in body tissues, cells are known by unusual changes called hyperplasia and dysplasia. In hyperplasia, the number of cells in an oxygen or tissue increases, which is normal under a microscope. In dysplasia, the cells look unusual under the microscope but are not cancerous. Hyperplasia and dysplasia can not be cancer or may be.

Credit: Terese Winslow

Types of cancer

More than 100 types of cancers are the type of cancer commonly given name for those organs or tissues where there are cancerous. For example, lung cancer begins in lung cells, and cerebral cancer begins in brain cancer cells. Cancer can also be described as the type of cells that make them, such as epithelial cells or squamous cells

You can search NCI's website based on cancer status or on the basis of list of cancer jade, for specific types of cancer information. We have a collection of information about childhood cancer and cancer in adolescence and young adults.

Here are some types of cancers that start in specific types of cells:

Carcinoma

Carcinoma is the most common type of cancer, they are formed by epithelial cells, cells which cover the inside and outer surfaces of the body. There are several types of epithelial cells, which are often like a column when viewed under a microscope.

Carcinoma specific names, starting in different epithelial cell types, are:

Adenocarcinoma is a cancer that is used in epithelial cells that produce fluid or mucus. This type of tissue of epithelial cells is sometimes called glandular tissues. Most cancers of breast, colon and prostate are adenocarcinoma

Basal cell carcinoma is a cancer that starts from the lower or basal layer of epidermis, which is an outer layer of the skin.

Squamous cell carcinoma is cancer which occurs in squamous cells, which are epithelial cells which are located under the outer surface of the skin. Squamous cells also line many other organs including stomach, intestines, lungs, bladder and kidneys. Squamous cells look like flat, such as the mask scale, when seen under the microscope, squamous cell carcinoma is sometimes called epidermoid carcinoma.

Transitional cell carcinoma is a cancer that occurs in a type of epithelium tissue called transitional epithelium or urontylium. This tissue, which is composed of several layers of epithelial cells, which can be large and small, is found in the lining of the bladder, urine, and kidneys (swelling of the kidneys), and some other organs. Some cancers of bladder, ureters, and kidneys are transitional cell carcinomas.

Sarcoma

Soft tissues of the body are located around the sarcoma, muscles, stomata, fats, blood vessels, lymph vessels, tissues of the nerves and joints.

Sorcomic cancers are in bone and soft tissues, including muscles, fats, blood vessels, lymph vessels and fibrous tissues (such as tendons and ligaments).

The most common types of osteosarcoma bone are the most common types of soft tissue sarcoma, leiomyosarcoma, Kaposi sarcoma, malignant fibrous histiocytoma, liposarcoma, and dermatifiaroscara Proteberan.

Our page has more information on soft tissue sarcoma.

Leukemia

The cancer that begins in the tissues of bone marrow formation is called leukemia. These cancers do not form solid tumors; Instead, a large number of abnormal white blood cells (leukemia cells and leukemic detonation cells) are produced in the blood and bone marrow, congestion of normal blood cells. Low levels of normal blood cells can make the body difficult for its tissues to obtain oxygen, bleed control, or infection infections.

There are four common types of leukemia, which are classified on the basis of how quickly the disease (acute or chronic) and on the type of blood cell start in the cancer (lymphoblastic or myeloid).

More information on our page on Leukemia

Lymphoma

Lymphoma is a cancer that starts in lymphocytes (T cells or B cells). This is a disease that deals with white blood cells which are part of the immune system. In lymphoma, abnormal lymphocytes are formed in lymph nodes and lymph vessels, as well as in other parts of the body.

There are two main types of lymphoma:

Hodgkin lymphoma - People with this disease are abnormal lymphocytes called Reid-Sternberg cells. These cells are usually made from B cells.

Non-Hodgkin lymphoma - This is a large group of cancers that starts in lymphocytes. Cancer can grow rapidly or slowly and can be from B cells or T cells.

There is more information on our page on lymphoma

multiple myeloma

Multiple myeloma is cancer that starts in plasma cells, another type of immune cell. Abnormal plasma cells, called brain cells, are made in bone marrow and form tumors in all bones through the body. Multiple myeloma is also called plasma cell myeloma and kehler disease.

Our page has more information on multiple mellocomas and other plasma cell neoplasms.

Melanoma

Melanoma is cancer which starts in cells which are called melanocytes, which are special cells that make melanin (pigment that gives skin color). Most melanoma are on the skin, but melanoma also comes in other pigment tissues, such as the eye.

Our page has more information on skin cancer and intococular malanoma.

Brain and spinal cord tumors

There are different types of brain and spinal cord tumors. The name of the tumor is based on the type of cell in which he was formed and where the tumor was first formed in the central nervous system. For example, astrocytic tumor starts with starter-shaped brain cells called astrocytes, which help keep nerve cells healthy. Brain tumors can be benign (not cancerous) or lethal (cancer)

Our page has more information on brain and spinal cord tumors in adults as we have information about brain and spinal cord tumors in children.

Other types of tumor

Germ cell tumor

Germ cell tumor is a type of tumor that starts in cells that give rise to sperm or egg. These tumors can be almost anywhere in the body and can either be benign or fatal

The body location / system includes a list of germ cell tumors containing links to more information on our cancer page.

Neurorendocrin tumor

Neuroendocrine is made up of tumor cells which release hormones in the blood in response to an indication from the nervous system. These tumors, which can be in excess of hormones, can cause many different symptoms. Neurondroclin tumor can be benign or fatal

We have more information in our definition of neuroendocrinin tumor.

Carcinoid tumor

Carcinoid tumors are a type of neuroendocrine tumor. They are slow-growing tumors which are usually found in the gastrointestinal system (often in the rectum and small intestines). Carcinoid tumors can spread to the liver or other sites in the body, and they can cause carotenin or prostaglandin-like substances due to castration syndrome.

Our page has more information on gastrointestinal carcinoid tumors.