“Marijuana Fights Cancer, Cristina Sanchez, a young biologist at Complutense University in Madrid, was studying cell metabolism when she noticed something peculiar. She had been screening brain cancer cells because they grow faster than normal cell lines and thus are useful for research purposes. But the cancer cells died each time they were exposed to tetrahydrocannabinol (THC), the principal psychoactive ingredient of marijuana.”

Source: http://todaynewsgazette.com/marijuana-fights-cancer/