Cancer is a group of more than 100 different diseases.
Cancer occurs when cells become abnormal, divide and form more cells without control or order.
All organs of the body are made up of cells. Normally, cells divide to produce more cells only when the body needs them. If cells keep dividing when new cells are not needed, a mass of tissue forms. This mass of extra tissue, called a growth or tumor can be benign or malignant. Benign tumors are not cancer.