The Beginning Steps
Cancer starts off as a regular cell. Most cells have an expected life cycle of growth, reproduction and death. A cancerous cell, however, has somehow gone wrong and not completed the cycle normally. A cancerous cell may split abnormally, not die or merge with other cancer cells. Either way, a cancer cell does something out of the ordinary and it usually starts in the upper layers of the body's organs called the epithelium.
The Cancerous Tumor Grows
Eventually the tumor grows to where oxygen and other life-sustaining nutrients do not reach the center of the cancerous cell. The inner parts of the tumor mass die off. At this point, the outer layers come inside and the growth cycle of the tumor is sustained.
Invasion
Because of the sustaining cycle of the inner cancerous cells dying and regrowing, the cancer cell can break down its membrane. When this happens, the cancer cell releases the MMP protein, which can break through the epithelium. The breaking of the membrane and epithelium creates a path for the cancerous tumor cells to move freely into the blood vessels and attack other parts of the body.
Tags: cancer cell, cancerous cell