Cancer refers to a type of disease that occurs when cells in the body experience certain changes that cause them to grow and divide out of control. These cells grow at a rapid rate, and they can travel through the blood and lymph systems and affect other organs in the body. If the immune system fails to locate and destroy these damaged cells, a tumor can develop.
Types of Cancer
Over 100 different kinds of cancer have been identified, and they are named according to the type of cell or organ in which they begin. They are divided into several categories, which include:
- Sarcoma: Cancer that starts developing in a muscle, bone, fat, cartilage, blood vessel, or other supportive or connective tissue.
- Carcinoma: Cancer that starts in the skin or tissues lining the internal organs.
- Lymphoma and myeloma: Cancers that start in the immune system’s cells.
- Leukemia: Cancer that starts in a tissue that produces blood, such as the bone marrow.
- Central nervous system cancers: Cancers that start in the brain and spinal cord tissues.
Causes of Cancer
The reason behind the development of cancer varies from one person to another, and sometimes, it cannot be clearly determined. There are certain risk factors that are known to raise the risk of cancer, but they do not cause cancer in everybody who has them. These risk factors include:
- advancing age
- passing on of gene mutations from parent to child
- menopausal hormone therapy
- infection with viruses such as human papillomavirus (HPV) and Epstein-Barr virus
- overexposure to ultraviolet radiation
- overexposure to ionizing radiation
- overexposure to chemicals and substances such as benzene, nickel, and asbestos
- being overweight, poor diet, and inactive lifestyle
- overconsumption of alcohol
- tobacco smoking