Cells become cancer cells because of damage to DNA. DNA is in every cell and directs all its actions.
In a normal cell, when DNA is damaged the cell either repairs the damage or the cell dies. In cancer cells, the damaged DNA is not repaired, but the cell doesn’t die like it should. Instead, this cell goes on making new cells that the body does not need. These new cells will all have the same damaged DNA as the first cell does.
Cancer can begin when cells grow out of control. Cells in nearly any part of the body can become cancer, and can spread to other areas of the body.
The types of cancers that develop in children are often different from the types that develop in adults. Childhood cancers are often the result of DNA changes in cells that take place very early in life, sometimes even before birth. Unlike many cancers in adults, childhood cancers are not strongly linked to lifestyle or environmental risk factors.
Cancers in children are different from cancers in adults, and the tolerance to treatments is also different.