Cancer

CancerFrom Wikipedia, the free encyclopediaJump to: navigation, search
For other uses, see Cancer (disambiguation).
Cancer
Classification and external resources

A coronal CT scan showing acancer of right pleural membranes, the outer surface of the lung and inner surface of the chest wall, malignant mesothelioma.
Legend: → tumor ←, ★ central pleural effusion, 1 & 3 lungs, 2 spine, 4ribs, 5 aorta, 6 spleen, 7 & 8 kidneys, 9 liver.
ICD-10 D00.
ICD-9 140—239
DiseasesDB 28843
MedlinePlus 001289
MeSH D009369

Cancer /ˈkænsər/ ( listen) (medical term: malignant neoplasm) isa class of diseases in which a group of cells display uncontrolled growth, invasion that intrudes upon and destroys adjacent tissues, and sometimes metastasis, or spreading to other locations in thebody via lymph or blood. These three malignant properties of cancers differentiate them from benign tumors, which do not invade or metastasize.

Researchers divide the causes of cancer into twogroups: those with an environmental cause and those with a hereditary genetic cause. Cancer is primarily an environmental disease, though genetics influence the risk of some cancers.[1] Commonenvironmental factors leading to cancer include: environmental pollutants, diet and obesity, tobacco, infections, radiation, and lack of physical activity.[1] These environmental factors cause or enhanceabnormalities in the genetic material of cells.[2] Cell reproduction is an extremely complex process that is normally tightly regulated by several classes of genes, including oncogenes and tumor suppressorgenes. Hereditary or acquired abnormalities in these regulatory genes can lead to the development of cancer. A small percentage of cancers, approximately five to ten percent, are entirely hereditary.The presence of cancer can be suspected on the basis of symptoms, or findings on radiology. Definitive diagnosis of cancer, however, requires the microscopic examination of a biopsy specimen. Most...