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.