Cancer is the name given to a set of more than 100 diseases that have in common the disordered (malignant) growth of cells that invade the tissues and organs, and can spread (metastasize) to other regions of the body.
Dividing rapidly, these cells tend to be very aggressive and uncontrollable, resulting in the formation of tumors (cancerous cell accumulation) or malignant neoplasms. On the other hand, a benign tumor simply means a localized mass of cells that multiply slowly and resemble their original tissue, rarely constituting a life risk.
The different types of cancer correspond to various types of cells in the body. For example, there are several types of skin cancer because the skin is made up of more than one type of cell. If the cancer begins in epithelial tissues such as skin or mucous membranes, it is called carcinoma. If it begins in connective tissues like bone, muscle or cartilage, it is called sarcoma.
Other features that differentiate many types of cancer from each other are the multiplication of the cells and an ability to invade neighboring or distant tissues and organs (metastasis).
Source: Instituto Nacional do Câncer – INCAwww.inca.gov.br