Cancer is a name for many diseases that affect different parts of the body. Cancer means that certain cells in the body are growing too fast. These cells don’t look, act, or work like normal cells. Normal cells in the body grow, divide, and die in an orderly way. Cancer cells do not know when to stop growing and dividing. This abnormal growth may crowd out normal cells or cause normal tissue to die. Cancer cells can also clump together and form a tumor.
Many parents wonder what caused their child’s cancer. Some parents feel responsible or guilty, they may worry that it was caused by something in their home, a lack of vitamins, or something they did or did not do. While scientists continue to look for genetic and environmental risk factors, currently the causes of childhood cancers are largely unknown. In addition, cancer is not contagious. You cannot catch it from another person.
Most childhood cancers arise from non-inherited changes (or mutations) in the genes of growing cells. When cells divide, all of the genetic information contained in the cells (called DNA) must be copied. During the process, the cell has a “spellchecker” much like that in a computer word processing system. The spell-checker is good, but not perfect. Some errors may be missed. While most errors change the cell and result in the cell dying, some errors may result in abnormal growth of the cell. This change in the cell may result in cancer. Because these errors seem to occur unpredictably and randomly, there is currently no known way to prevent them.
Cancers are grouped by the type of cells affected. The most common types of childhood cancers are:
- Leukemia, a cancer of white blood cells that starts in bone marrow cells
- Lymphoma, a cancer of white blood cells that starts in the lymph nodes located throughout the body
- Brain and spinal cord tumors, cancer of cells of the central nervous system
- Sarcoma, a cancer of connective muscle and bone tissues
- Embryonal tumors, cancers of the reproductive system, liver, or kidney