Adam Yauch, a founding member of the pioneering Beastie Boys hip hop group, died Friday at the age of 47.

Yauch, who also was known as MCA, helped start the group in 1979 when it was a hardcore punk bank. But as its music evolved, the Beastie Boys produced some of hip-hop's celebrated albums, including Licensed to Ill, Paul's Boutique, Check Your Head and Ill Communication. Yauch was a vocalist and bass player.

The group has not performed live since 2009, but was inducted last month into the Rock and Roll Hall of Fame.

The cause of Yauch's death was not immediately known. But he had been in treatment for cancer since 2009 when a tumor was discovered in his salivary gland.