what is cancer, How do you explain it?

Question

Is it something of owr own cells or external?

Answer 1

Cancer is a class of diseases or disorders characterized by uncontrolled division of cells and the ability of these cells to invade other tissues, either by direct growth into adjacent tissue through invasion or by implantation into distant sites by metastasis. Metastasis is defined as the stage in which cancer cells are transported through the bloodstream or lymphatic system. Cancer may affect people at all ages, but risk tends to increase with age. It is one of the leading causes of death in developed countries.

There are many types of cancer. Severity of symptoms depends on the site and character of the malignancy and whether there is metastasis. A definitive diagnosis usually requires the histologic examination of tissue by a pathologist. This tissue is obtained by biopsy or surgery. Most cancers can be treated and some cured, depending on the specific type, location, and stage. Once diagnosed, cancer is usually treated with a combination of surgery, chemotherapy and radiotherapy. As research develops, treatments are becoming more specific for the type of cancer pathology. Drugs that target specific cancers already exist for several cancers. If untreated, cancers may eventually cause illness and death, though this is not always the case.

The unregulated growth that characterizes cancer is caused by damage to DNA, resulting in mutations to genes that encode for proteins controlling cell division. Many mutation events may be required to transform a normal cell into a malignant cell. These mutations can be caused by chemicals or physical agents called carcinogens, by close exposure to radioactive materials, or by certain viruses that can insert their DNA into the human genome. Mutations occur spontaneously, or are passed down generations as a result of germ line mutations.

Many forms of cancer are associated with exposure to environmental factors such as tobacco smoke, radiation, alcohol and certain viruses. While some of these can be avoided, there is no known way to entirely avoid the disease, and public health and vaccination programs are also important on a global scale.

The following closely related terms may be used to designate abnormal growths:

Neoplasia and neoplasm are the accurate, scientific names for this group of diseases as defined in the first paragraph above. This group contains a large number of different diseases; the usual classification is listed below. Neoplasms can be benign or malignant.
Cancer is a widely used word that is usually understood as synonymous with malignant neoplasm. Occasionally, it is used instead of carcinoma, a sub-group of malignant neoplasms. Because of its overwhelming popularity relative to 'neoplasia', it is used frequently instead of 'neoplasia', even by scientists and physicians, especially when discussing neoplastic diseases as a group.
Tumor in medical language simply means swelling or lump, either neoplastic, inflammatory or other. In common language, however, it is synonymous with 'neoplasm', either benign or malignant. This is inaccurate since some neoplasms usually do not form tumors, for example leukemia or carcinoma in situ.
Cancers are classified by the type of cell that resembles the tumor and, therefore, the tissue presumed to be the origin of the tumor. The following general categories are usually accepted:

Carcinoma: malignant tumors derived from epithelial cells. This group represent the most common cancers, including the common forms of breast, prostate, lung and colon cancer.
Lymphoma and Leukemia: malignant tumors derived from blood and bone marrow cells
Sarcoma: malignant tumors derived from connective tissue, or mesenchymal cells
Mesothelioma: tumors derived from the mesothelial cells lining the peritoneum and the pleura.
Glioma: tumors derived from glia, the most common type of brain cell
germ cell tumours: tumors derived from germ cells, normally found in the testicle and ovary
Choriocarcinoma: malignant tumors derived from the placenta
Malignant tumors are usually named using the Latin or Greek root of the organ as a prefix and the above category name as the suffix. For instance, a malignant tumor of liver cells is called hepatocarcinoma; a malignant tumor of the fat cells is called liposarcoma. For common cancers, the English organ name is used. For instance, the most common type of breast cancer is called ductal carcinoma of the breast or mammary ductal carcinoma. Here, the adjective ductal refers to the appearance of the cancer under the microscope, resembling normal breast ducts.

Benign tumors are named using -oma as a suffix. For instance, a benign tumor of the smooth muscle of the uterus is called leiomyoma (the common name of this frequent tumor is fibroid). This nomenclature is however somewhat inconsistent, since several "malignant" tumor growths also have this suffix in their names, e.g. neuroblastoma, lymphoma and melanoma.

Origins of cancer
Cell division or cell proliferation is a physiological process that occurs in almost all tissues and under many circumstances. Normally the balance between proliferation and programmed cell death is tightly regulated to ensure the integrity of organs and tissues. Mutations in DNA that lead to cancer disrupt these orderly processes.

The uncontrolled and often rapid proliferation of cells can lead to either a benign tumor or a malignant tumor (cancer). Benign tumors do not spread to other parts of the body or invade other tissues, and they are rarely a threat to life unless they extrinsically compress vital structures. Malignant tumors can invade other organs, spread to distant locations (metastasize) and become life-threatening.

Answer 2

Cancer

Cancer is a disease of cells. It is an abnormal growth of cells which tend to proliferate in an uncontrolled way and, in some cases, to metastasize (spread).

Cancer is also called malignancy. A cancerous growth or tumor is sometimes referred to as a malignant growth or tumor. A non-malignant growth or tumor is referred to as benign. Benign tumors are not cancer.

Cancer is not one disease. It is a group of more than 100 different and distinctive diseases. Cancer is NOT contagious.

Cancer can involve any tissue of the body and have many different forms in each body area. Most cancers are named for the type of cell or organ in which they start. If a cancer spreads (metastasizes), the new tumor bears the same name as the original(primary) tumor.

The frequency of a particular cancer may depend on gender. While skin cancer is the most common type of malignancy for both men and women, the second most common type in men is prostate cancer and in women, breast cancer.

Cancer frequency does not equate to cancer mortality. Skin cancers are often curable. Lung cancer is the leading cause of death from cancer for both men and women in the United States today.

Cancer is the Latin word for crab. The ancients used the word to mean a malignancy, doubtless because of the crab-like tenacity a malignant tumor sometimes seems to show in grasping the tissues it invades. Cancer may also be called malignancy, a malignant tumor, or a neoplasm (literally, a new growth).

For detailed information about specific types of cancer, please read the articles which address specific cancers such as Bladder Cancer, Bone Cancer, and so on.

Answer 3

Lot of good, long winded explanations. In short, something has caused a mutation in your own cells. Could be from chemicals, viruses, or radioactive material etc, etc. Each cell in your body is pre programmed to die, programmed cell death is known as "Apoptosis". In a cancerous cell, a mutation has occurred, or an error in a signaling pathway that allows the cell to continue to grow and live even though it should have killed itself. The cancerous cell then continues to divide eventually resulting in a tumor. That is my basic understanding of how it works. Hope that helps!

Answer 4

Cancer is a mutation of cells that occurs during DNA replicationr cell replication, also known as mitosis and meiosis.

Causes of cancer are called mutagens. Can include: smoking, radiation, x-rays and other environmental things.

Answer 5

Cancer develops when cells in a part of the body begin to grow out of control. Although there are many kinds of cancer, they all start because of out-of-control growth of abnormal cells.

Normal body cells grow, divide, and die in an orderly fashion. During the early years of a person's life, normal cells divide more rapidly until the person becomes an adult. After that, cells in most parts of the body divide only to replace worn-out or dying cells and to repair injuries.

Because cancer cells continue to grow and divide, they are different from normal cells. Instead of dying, they outlive normal cells and continue to form new abnormal cells.

Cancer cells develop because of damage to DNA. This substance is in every cell and directs all activities. Most of the time when DNA becomes damaged the body is able to repair it. In cancer cells, the damaged DNA is not repaired. People can inherit damaged DNA, which accounts for inherited cancers. More often, though, a person's DNA becomes damaged by exposure to something in the environment, like smoking.

Cancer usually forms as a tumor. Some cancers, like leukemia, do not form tumors. Instead, these cancer cells involve the blood and blood-forming organs and circulate through other tissues where they grow.

Often, cancer cells travel to other parts of the body where they begin to grow and replace normal tissue. This process is called metastasis. Regardless of where a cancer may spread, however, it is always named for the place it began. For instance, breast cancer that spreads to the liver is still called breast cancer, not liver cancer.

Not all tumors are cancerous. Benign (noncancerous) tumors do not spread (metastasize) to other parts of the body and, with very rare exceptions, are not life threatening.

Different types of cancer can behave very differently. For example, lung cancer and breast cancer are very different diseases. They grow at different rates and respond to different treatments. That is why people with cancer need treatment that is aimed at their particular kind of cancer.

Cancer is the second leading cause of death in the United States. Half of all men and one third of all women in the United States will develop cancer during their lifetimes. Today, millions of people are living with cancer or have had cancer. The risk of developing most types of cancer can be reduced by changes in a person's lifestyle, for example, by quitting smoking and eating a better diet. The sooner a cancer is found and treatment begins, the better are the chances for living for many years.

Answer 6

The doctor told us is was a cell that had been dormant and turned into a cancer possibly from stress or aggravation. I don't think they really know but they have to tell you something.

Answer 7

cells that mutate and then invade other cells,
can be external things because some things like radiation enter the cell and cause it to mutate, therefore causing cancer.
sometimes its not external influences because for example breast cancer is thought to be hereditary and causes arent known
hope this helps i no its not as in depth as previous answer but maybe easier to understand?
=]

Answer 8

1

Answer 9

Cells...
Like out-of -control children... often you CAN find a remedy

Answer 10

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