Cancer

hide

Cancer (medical term: malignant neoplasm) is a class of diseases in which a group of cells display uncontrolled growth (division beyond the normal limits), invasion (intrusion on and destruction of adjacent tissues), and sometimes metastasis (spread to other locations in the body via lymph or blood). These three malignant properties of cancers differentiate them from benign tumors, which are self-limited, and do not invade or metastasize. Most cancers form a tumor but some, like leukemia, do not. The branch of medicine concerned with the study, diagnosis, treatment, and prevention of cancer is oncology.

Cancer may affect people at all ages, even fetuses, but the risk for most varieties increases with age. Cancer causes about 13% of all human deaths. According to the American Cancer Society, 7.6 million people died from cancer in the world during 2007. Cancers can affect all animals.

Nearly all cancers are caused by abnormalities in the genetic material of the transformed cells. These abnormalities may be due to the effects of carcinogens, such as tobacco smoke, radiation, chemicals, or infectious agents. Other cancer-promoting genetic abnormalities may be randomly acquired through errors in DNA replication, or are inherited, and thus present in all cells from birth. The heritability of cancers are usually affected by complex interactions between carcinogens and the host's genome. New aspects of the genetics of cancer pathogenesis, such as DNA methylation, and microRNAs are increasingly recognized as important.

Genetic abnormalities found in cancer typically affect two general classes of genes. Cancer-promoting oncogenes are typically activated in cancer cells, giving those cells new properties, such as hyperactive growth and division, protection against programmed cell death, loss of respect for normal tissue boundaries, and the ability to become established in diverse tissue environments. Tumor suppressor genes are then inactivated in cancer cells, resulting in the loss of normal functions in those cells, such as accurate DNA replication, control over the cell cycle, orientation and adhesion within tissues, and interaction with protective cells of the immune system.

Diagnosis usually requires the histologic examination of a tissue biopsy specimen by a pathologist, although the initial indication of malignancy can be symptoms or radiographic imaging abnormalities. 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 different varieties of cancer. There has been significant progress in the development of targeted therapy drugs that act specifically on detectable molecular abnormalities in certain tumors, and which minimize damage to normal cells. The prognosis of cancer patients is most influenced by the type of cancer, as well as the stage, or extent of the disease. In addition, histologic grading and the presence of specific molecular markers can also be useful in establishing prognosis, as well as in determining individual treatments.

For more information about Cancer, read the full article at Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.

News tagged with cancer

results timeline

Reasonable alternative to invasive biopsy of palpable breast lesions with benign imaging features identified

Medicine & Health / Cancer

1hour ago | not rated yet | 0

Short-term follow-up is a reasonable alternative to invasive biopsy of palpable (capable of being touched or felt) breast lesions with benign imaging features, particularly in younger women with probable fibroadenoma (non-cancerous ...

Sponges against cancer

Biology / Cell & Microbiology

4 hours ago | not rated yet | 0

Deep under the sea, there's a battle of life and death going on, with no holds barred. Sponges and other marine animals which cannot move around might seem to be defenceless against predators. Yet nothing is further from ...

Radiology procedure may help increase long-term survival in patients with severe liver cancer

Medicine & Health / Cancer

5 hours ago | not rated yet | 0

In patients with unresectable (unable to be removed by surgery) liver cancer, an interventional radiology procedure called triple-drug transcatheter arterial chemoemobolization (TACE) followed by a liver transplant may significantly ...

Researchers identify role of gene in tumor development, growth and progression

Medicine & Health / Cancer

5 hours ago | not rated yet | 0

Virginia Commonwealth University Massey Cancer Center and VCU Institute of Molecular Medicine researchers have identified a gene that may play a pivotal role in two processes that are essential for tumor development, growth ...

When It Comes to Drug Delivery, Size Matters

Nanotechnology / Bio & Medicine

10 hours ago | 5 / 5 (1) | 0

(PhysOrg.com) -- One of the great promises of nanotechnologies lies in its ability to create drug-containing nanoparticles decorated with targeting molecules that recognize and bind to cancer cells, providing drug delivery ...

Report: 20-somethings can go 2 years between Paps

Medicine & Health / Health

11 hours ago | not rated yet | 0

(AP) -- Most women in their 20s can have a Pap smear every two years instead of annually, say new guidelines that conclude that's enough to catch slow-growing cervical cancer.

Laser therapy can aggravate skin cancer

Medicine & Health / Cancer

12 hours ago | not rated yet | 0

High irradiances of low-level laser therapy (LLLT) should not be used over melanomas. Researchers writing in the open access journal BMC Cancer studied the pain relieving, anti-inflammatory 'cold laser', finding that it cau ...