February 4 is World Cancer Day. The theme of this year's Cancer Day is "Do you know about cancer?" Among various diseases, cancer is the "number one killer". On January 10, 2013, the China Cancer Registration Center released the 2012 China Cancer Registration Annual Report, which showed that 6 people were diagnosed with cancer every minute. But in fact, 40% of cancers are preventable. Is cancer terrible? How to prevent and cure?