Cancer is a disease in which some of the body’s cells grow uncontrollably and spread to other parts of the body. Cancer can start almost anywhere in the human body, which is made up of trillions of cells. When cells grow old or become damaged, they die, and new cells take their place.

Cancer develops when the body’s normal control mechanism stops working. Old cells do not die and instead grow out of control, forming new, abnormal cells. These extra cells may form a mass of tissue, called a tumor. Some cancers, such as leukemia, do not form tumors.

Sometimes the process of cell division breaks down, and abnormal or damaged cells grow and multiply when they shouldn’t. These cells may form tumors, which are lumps of tissue. Tumors can be cancerous or not cancerous (benign).

Cancerous tumors and benign tumors are two types of tumors.

Cancerous spread into, or invade, nearby tissues and can travel to distant places in the body to form new tumors.

Benign tumors do not spread into, or invade, nearby tissues. When removed, benign tumors usually don’t grow back, whereas cancerous tumors sometimes do.

*Invade into nearby areas and spread to other areas of the body.
*Ignore signals that normally tell cells to stop dividing or to die.
*Trick the immune system into helping cancer cells stay alive and grow.

Anyone can get cancer, although the risk goes up with age.

Pain, weight loss, fever, fatigue, cough, unusual bleeding, difficulty in swallowing, thickening of any part of the body are the common symptoms of cancer.

A carcinogen is any substance, radionuclide, or radiation that promotes carcinogenesis or the formation of cancer. This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes.