Cancer The human body is constantly creating new cells and destroying or resorbing old cells as a part of the normal physiology. Cancer is a group of diseases characterised by a loss of normal cell growth control. In normal tissues, the rates of new cell growth and old cell death are kept in balance. In cancer, this balance is disrupted. This disruption can result from uncontrolled cell growth or loss of a cell’s ability to undergo “apoptosis”. Apoptosis, or “cell suicide,” is the mechanism by which old or damaged cells normally self-destruct. .The resulting malignant overgrowth of cells, which continue to divide and multiply completely unchecked within the body, usually ultimately consume the other normal cells and thereby debilitate or kill the patient. Cancers arise from the cells of one organ or tissue and the cancer is then said to have arisen from that tissue. However, the cells tend to shed off and spread to other sites in the body by the blood or lymphatic systems in particular, and then these secondary seedlings (also called metastases) grow at these new body sites to damage the normal tissue at these sites also. Cancer is caused by both external factors (tobacco, chemicals, radiation and infectious organisms) and internal factors (inherited mutations, hormones, immune conditions, and mutations that occur from metabolism). Causal factors may act together or in sequence to initiate or promote carcinogenesis. Ten or more years often pass between exposure or mutations and detectable cancer. Caner is treated by surgery radiation, chemotherapy, hormones and immunotherapy.