The human body is made up of millions of cells that vary in shape, size and function. Cells are the building blocks of all the different tissues in the body.
In healthy tissues, new cells are created through cell division, a process called mitosis. When cells get old, they ‘destroy themselves’. This process is called apoptosis.
There must be a careful balance between the production of new cells and the death of old cells. Cancer occurs when that balance is disturbed because cells start dividing uncontrollably. This disruption can be the result of uncontrolled cell growth or the fact that cells are no longer able to self-destruct. The resulting clump of cells is called a tumor.
A benign, or benign tumor, is the overgrowth of cells that appear normal. These cells remain where they originated. Malignant, or malignant, cells can travel through the circulatory system or the lymphatic system to other parts of the body and create new tumors there. This process is called metastasis.
Various forms of cancer are distinguished according to the place where they originated. That place is called the primary location. if lung cancer spreads to the brain, the brain tumor is considered metastatic lung cancer, not brain cancer. The brain tumor is then considered the secondary site.
