Cancer refers to a group of more than 100 distinct diseases characterised by the uncontrolled growth of abnormal cells in the body. Cancer affects one in every three persons born in developed countries and is a major cause of sickness and death throughout the world. Though it has been known since antiquity, significant improvements in cancer treatment have been made since the middle of the 20th century, mainly through a combination of timely and accurate diagnosis, selective surgery, radiation therapy, and chemotherapeutic drugs.