Tissues are combined to make organs. Organs in turn make up organ systems. Lastly, organ systems make the body. Tissues in the body will naturally lose cells over time, so replacement of the old cells is necessary. When cells fail to develop or mature properly, they may become abnormal or cancerous.
Cancer is the second leading cause of death among adults.
Cancer is classified by the part of the body in which it begins and by its appearance under a microscope. It is estimated that there are over 200 different types of cancers. According to the American Cancer Society, it is estimated that there will be about 1,220,100 new cancer cases to be diagnosed in the year 2000. An individual's risk for cancer can be reduced through a variety of ways or means. To learn more, visit the Cancer Resource Center at the American Cancer Society's homepage .