Cancer is defined in most dictionaries is “the spreading of any evil.” Cancer is a definite evil, a disease of uncontrolled cell growth. It is a major health problem in our society and is second only to heart disease as a cause of death in the United States. More than one million people develop cancer each year.
The Development of Cancer
Our bodies go through a process of normal cell growth in which cells divide when new cells are required. Normally cells stop dividing when this need is met. Tumors are caused when our body is not signaling the end of cell division properly.
The changes in cell behavior may be due to genetic material in our cells. A tumor suppressor gene is supposed to stop abnormal division of the cells but if this gene is lost or is damaged a tumor can develop. If a proto-oncogene is activated it can lead to changes that cause our body cells to lose control of what happens when they divide.
The characteristics of cancerous tumors are uncontrolled cell growth, damage to healthy tissues, and the ability to metastasize, or spread.
Both benign and malignant tumors are abnormal. A benign tumor is encased in a membrane that keeps it from getting to other body tissues. Benign tumors are not considered to be cancerous but can cause damage to healthy tissues when the mass is large enough to compress them. A malignant tumor is much more dangerous and harmful than a benign tumor. A malignant tumor is cancerous because the cells are not encased in a membrane and can invade and destroy nearby tissues.
Cancerous cells can travel throughout the body via the circulatory system or the lymphatic system causing secondary cancers. The cancer is said to metastasize when this happens. The secondary cancers are also known as metastases.