Adam Yauch, best known as MCA of the legendary Beastie Boys, has died after a long battle with cancer. 

The 47-year-old first revealed his illness in 2009. Despite rumors that he was cancer-free last year, Yauch took to the band's website and informed fans that he was continuing treatment. There was recent confirmation that his health had continued to decline, as he was unable to participate when the Beastie Boys were inducted into the Rock and Roll Hall of Fame this past March. The Beastie Boys were the third group to join the Rock and Roll Hall of Fame. The ceremony will air on Saturday, May 5th on HBO

MCA and band mates Michael "Mike D" Diamond, and Adam "Ad-Rock" Horovitz formed the Beastie Boys in 1979. Since then, they have released eight albums, toured the world and participated in a number of activist movements, most notably by organizing the Tibetan Freedom Concerts which ran from 1996 to 2001.