What is cancer?
Cancer is a disease caused by uncontrolled cell proliferation in different organs or tissues.
Most carcinogenic cells generate a growth called tumor which causes alterations in the body according to localization and aggressiveness.
Amongst the different tumors, there exist some of higher aggressiveness that is determined by the capacity to directly invade tissues or travel through the body and lodge in areas that are distant from the primary growth, which is known as metastasis.
The central problem of the appearance of cancer is that there is an alteration in the cell biological clock.
Normal cell growth and death are determined by genetic and environmental factors; tumor cells undergo such a change as to become unsociable.
The normal genetic cell programming may be altered by different agents (smoking, sun exposure, etc) that determine that the cells acquire greater autonomy and uncontrolled growth occurs.
The alteration of a single gene is not sufficient for cancer to appear, most human tumors are due to an aggregation of genetic alterations that are not deadly for the cell.