Cancer is a disease in which cells grow and divide with little or no control. There are many different types of cancer. Cancers are typically named for the organ or the cell where the cancer begins. Some cancers can spread from the original site and move to other places in the body.
How Cancer Starts
Cells are the basic building blocks of the body. There are many different types of cells and they make up all of the tissues and organs in the body. Within each cell are thousands of genes (also known as genetic material) that act as a command center for the cell. Genes provide instructions for what role the cell will play in the body. Each gene has a unique job to perform either by itself, or in combination with other genes.
Cells divide to make new cells to replace damaged or old cells. As cells duplicate, they pass along copies of their genetic material to the new cells.
The process of cells dividing and passing along genes is usually well controlled, ensuring that the right kinds and numbers of cells are present for the different parts of the body to function correctly. The body and the cells can usually recognize when something has changed in a cell and will work to repair or destroy the abnormal cell.
What Causes Cancer
Cancer in children occurs when formerly-healthy cells mutate and replicate much more than they should. When that happens, they can also destroy nearby healthy cells and invade different parts of the body.
Researchers still do not know much about what causes cancer in children. Most children's cancers are caused by random genetic mutations that can lead to cancer. For some of these mutations, there are some environmental and genetic factors that can contribute to the cancer growing. But we still do not know what causes most childhood cancers.