Exactly what is cancer?

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, due to the fact that DNA damage becomes more apparent in aging DNA. It is one of the principal 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, and may be passed down from one generation to the next as a result of mutations within germ lines.

Many forms of cancer are associated with exposure to environmental factors such as tobacco smoke, radiation, alcohol, and certain viruses. While some of these risk factors can be avoided or reduced, there is no known way to entirely avoid the disease.-

Answer 2

Normal cells have internal controls to limit reproduction, even having a "terminate after X reproductions" instruction, which is one why why we are not immortal. Cancer cells are mutations which have lost this internal control over reproduction, so they multiply out of control, and sometimes can be immortal. Some cancer strains in laboratories have been taken from cancerous cells from a woman that have died over half a century ago, so in a sense, the strain is immortal.

Answer 3

Cancer is a disease of cell proliferation.

Cells undergo many complex changes that result in their uncontrolled proliferation. Normal cells divide only when they are signaled to do so, for example during development or when a wound is healed.

Cancerous cells divide without such signals. The damage that causes disease is as a result of this abnormal growth: the organ(s) affected can no longer function properly because the cancer cells are in the way.

Most advanced cancers also metastasize, which means that the cancer spreads throughout the body, attacking other organs in addition to the one initially affected.

Cancer is not like an infectious disease - it does not come from outside the body, but rather is the result of normal cell regulation going wrong.

The way this regulation goes wrong is complex, but consists of at least three elements: the cells acquire abnormal growth stimuli, they acquire the ability to survive conditions that normal cells would die in, and they acquire the ability to recruit blood supply from the body which they need to bring oxygen and nutrients to the tumor.

The reason cancer appears as many diseases, is because the nature of the disease, and the clinical course, depends on the cell type affected, as well as the particular changes, or mutations, that led to one particular cancer.

What all cancers share is that they are cell-proliferation diseases. Sometimes they also share other characteristics: for example, you may have heard of the p53 gene. It is what is called a tumor suppressor gene, meaning that its inactivation leads to cancer. Many different types of cancer have lost function of this gene.

Cancer starts when one cell undergoes an as yet poorly understood change. This change leads to the cell dividing more rapidly, and sets the scene for the next mutation to occur. Often the first mutation will also make it easier for more mutations to occur: for example the p53 gene ensures the intactness of the genome, and its loss makes it more likely for genetic alterations to occur. As far as we know at present, these mutations occur randomly, and the ones that make cells grow faster, and survive better are selected for. As more and more mutations accumulate, the cancer becomes more aggressive: in most cancers a progression from less to more aggressive forms can be seen.

Answer 4

It is where your cells repeated go through mitosis, i think that is the correct word for it. In cell reproductin your cells go through a few stages in order to make new one. In caner durning a certain stage, the process is messed up and it duplicates more than the cell needs it to. Mass production at this stage i think it it either prophase or antaphase makes the lumps that are consistantly felt for example in one's breats. Look at osmosis joins the movie it can help you bette runderstand what you cells go thrugh to make you a healther person, plus the movie is funny.

Answer 5

When something goes wrong inside any given cell in your body and stops that cell from controlling itself, the cell starts to grow out of control, and can also affect other cells around it to do the same, then a number of cells start to grow at a rapid rate, and all sorts of things start to go wrong and very quickly, that, is cancer, and it can affect any of the cells in your body, and each in a number of different ways. The cure is to try to either cut all of the cancerous cells out of your body, or kill them with some kind of poison or even radiation, but if even one of those crazy cells escapes and gets into your blood it can then travel around your body affecting other cells as it goes, then you have big, big trouble.

Answer 6

cancer is a mutation of the cell of the infected area. pancreatic cancer, has mutated pancreas cells, it is contagieous(not to humans but to cells) if most of that area is affected, it can spread. the less mutated cells, the better the chance of surviving.

Answer 7

any of more than 100 deaseses characterized by excessive, uncontrolable growth of abnormal cells, which invade and destroy other tissues. can develop in ANY part of the body. cancer usually develops over a long period of time.
hope this helps. :)

Answer 8

Uncontrolled growth and reproduction of mutated, harmful cells.

Answer 9

In general CANCER means over production of white blood cells(WBC)

Answer 10

Its a quick reproducing cell that invades other cells