"He really served as a great example for myself and so many of what determination, faith, focus, and humility coupled with a sense of humour can accomplish. The world is in need of many more like him. We love you Adam."
A number of stars have paid tribute to MCA - who founded the group with Kate Schellenbach, John Berry, and Michael Diamond (Mike D) in 1979 with Berry leaving in 1983 to be replaced by Ad-Rock - including Madonna, who took to her Facebook page to express her sadness about his passing.
She wrote: "The Beastie Boys were one of a kind! And so was Adam! They were all an important part of my musical history and integral to the musical revolution that was happening at the time. I'm very sad to hear about Adam's passing. God bless him and his family."
Jay-Z, Justin Timberlake and will.i.am have also paid tribute to Adam - who is survived by his wife, Dechen Wengdu, and their daughter, Losel - and the Dalai Lama, who blessed MCA last year, has praised the musician for his work with the Tibetan people.
A spokesperson for the Tibetan Buddhist leader said: "Adam had helped us raise awareness on the plight of the Tibetan people by organising various freedom Tibet concerts and he will be remembered by his holiness and the Tibetan people."
The Beastie Boys have not performed live since the summer of 2009, and Adam's illness prevented them from appearing in music videos for their album Hot Sauce Committee, Pt. 2.
- Bang! Showbiz