Cancer is an increasing health threat in China which has witnessed changes in life styles and a polluted environment. China reports 3.5 million new cases of cancer each year, while 2.5 million people lose their life to the disease every year in the country.The research team led by Professor Yan Guangmei of the Zhongshan School of Medicine, at Sun Yat-Sen University in Guangdong Province discovered the virus. It can be extracted from a certain kinds of mosquito in the tropical Hainan Province and can curb cancer cells' growth without affecting normal cells.Animal tests of the virus showed that M1 worked well on cancer cells of the liver, bladder, colon and rectum.The news of the discovery was published in the October edition of the Proceedings of the National Academy of Sciences of the United States of America.