what is a 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 or by droplet contamination of reachable structures away from the immediate vicinity. 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. However, some carcinogens also appear to work through non-mutagenic pathways that affect the level of transcription of certain genes without causing genetic mutation.

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

Cancer is any malignant growth or tumor caused by abnormal and uncontrolled cell division; it may spread to other parts of the body through the lymphatic system or the blood stream.

It is said that everybody accumulates enough DNA defects which become unrepairable over time to acquire cancer IF they live long enough.

Answer 3

Cancer is a malignant growth like a tumour in the body.It is a very painful disease,
very difficult to treat.Unless discovered in the very early stages a cancer patient may not survive for long.Its treatment lies in subjecting the body to radiations or chemotherapy.These treatments have side effects of their own

Answer 4

Usually half-hashed growth of Celle's(uncontrolled, unusual, erratic). This may have various reasons, Mutation due to chemical or radioactive exposure. or no reason system goes haywire.

In some case Leukaemia(blood Cancer) White cell go haywire and eat up red blood cells.

In some case lack of white cells (no immunity).

Answer 5

According to Webster's Medical Dictionary it is any malignant tumor. Malignant tumors endanger life, they choke out normal tissue as they extend to adjacent tissues layers. They may spread to other parts of the body (metastases). They may also spread by the blood and lymph systems. Malignant tumors are divided into 2 classes Carcinomas and Sarcomas. Carcinomas develop in the lining and covering tissues of organs, Sarcomas in the connective and supporting tissues of the body.(bone cancers are sarcomas)

Answer 6

Cancer is the rampant mutation of cells in your body, sometimes triggered by viruses and sometimes triggered by chemicals or other environmental influences.

Answer 7

someone born between June 22 and July 23

Answer 8

cancer! it's a terrible disease. it can make someone die. we have precautions to keep it away from us.it's worse than aids

Answer 9

uncontrolled growth and multiplication of unwanted cells.