Sometimes a group of cells change, grow differently and more quickly than the cells around them. These may become cancer cells. These cells grow into groups where other normal cells should be growing. This is called metastasis, and can start a secondary cancer. Anyone can get cancer.
Animals get cancer, so do plants.
Cancer is rare in children, more common in middle-aged people and most common in old people. The chance of getting certain cancers may increase as a person gets older and because of factors such as a person's sex, occupation, health habits, lifestyle and family history. The causes of many cancers are not yet known. Cancer cannot be caught. It is not infectious like a cold or the flu.