Cancer and its risk factors

Cancer is simply a disease due to excessive cell growth. Normal cell growth and development are tightly controlled by neural and hormonal mechanisms. Cancer usually originates from one cell which is out of control. It involves abnormal changes in its DNA (genetic material). This process usually takes years or even decades. The tendency to develop certain types of cancer can be passed on to the offspring. However, environmental or lifestyle factors are very important. These can be physical, chemical or biological. The major risk factors are ionizing radiation (from X-ray, gamma-ray, nuclear material, etc.), smoking or other forms of tobacco use, ultraviolet (from excessive sunshine, tanning bed, etc.), aromatic compounds (from benzine, smoked, grilled, broiled and fried food, etc.), other industrial materials such as certain dyes and asbestos, certain heavy metals such as arsenic, infection from biological pathogens such as human papilloma virus, biological toxins, prolonged non-healing wound or mechanical irritation, excessive alcohol or caloric intake. Host factors are mainly immune deficiency or suppression from viral infections or certain medical therapies.