You cannot catch cancer from someone who has it. Spending time with a loved one who has cancer will not cause you to get it too. Rarely will a person who has had an organ or tissue transplantation develop cancer from a donor who had cancer previously. Although cancer itself does not spread from person to person, certain viruses can increase your risk of getting cancer. Hepatitis B or C spreads through sexual intercourse or infected needles and increases your risk of getting liver cancer.