(CNN) -- Adam "MCA" Yauch, a founding member of the pioneering rap band Beastie Boys, died Friday after a nearly three-year battle with cancer, the band's publicist said.
A torrent of Twitter messages from entertainers lauded Yauch, 47, as a visionary musical artist, filmmaker and humanitarian.
"He stood for integrity as an artist. What a loss. He was a very good man," said actor Ben Stiller.
Yauch revealed in 2009 that he had a cancerous tumor in a salivary gland. As a result, the band canceled its scheduled concerts and delayed the release of an album.
"I started feeling this little lump in my throat, like you would feel if you have swollen glands or something like that, like you'd feel if you have a cold, so I didn't really think it was anything," he said then in a video to fans.
Yauch, a self-taught bassist and vocalist, underwent surgery to treat the tumor that year.
The Beastie Boys, who blended punk and rap, burst on the music scene in 1986 with the album "Licensed to Ill," which included hits such as "(You Gotta) Fight for the Right (to Party"), an anthem to teen angst; "Brass Monkey" and "No Sleep Till Brooklyn."
The group came together for the first time to play at Yauch's 17th birthday party, its publicist said.
Yauch was the oldest of the Beastie Boys, an only child who grew up in Brooklyn Heights, according to Current Biography magazine. The band, which also featured Michael "Mike D" Diamond and Adam "Adrock" Horovitz, sold more than 40 million records and had four No.1 records.
The Beastie Boys' success in hip-hop was notable at a time when the music form was dominated by African-American performers.
"The group's music crossed genres and color lines, and helped bring rap to a wider audience," said Neil Portnow, president of the Recording Academy.
Yauch was unable to attend the band's induction into the Rock & Roll Hall of Fame last month. Horovitz read Yauch's acceptance letter.
Under an alias, Yauch directed several Beastie Boys videos, including "Intergalactic" and "So What'cha Want."
Yauch converted to Buddism in the 1990s after visiting Nepal and hearing the Dalai Lama speak in Arizona, he told the Buddhist magazine Shambhala sun in 1995.
"It just seemed like Buddhism, especially Tibetan Buddhism -- because that's mainly what I've been exposed to -- was a real solid organization of teachings to point someone in the right direction," the magazine quoted him as saying. "Some real well thought out stuff. But I don't know, like, every last detail about Buddhism."
The conversion led him to have second thoughts about the bawdy party-boy image the band portrayed in the 1980s, he told the Boston Globe in 1998.
"I didn't realize how much harm I was doing back then and I think a lot of rap artists probably don't realize it now," the newspaper quoted him as saying. "I said a lot of stuff fooling around back then, and I saw it do a lot of harm. I had kids coming up to me and saying, 'Yo, I listen to your records while I'm smoking dust, man.' And I'd say, 'Hey, man, we're just kidding. I don't smoke dust.' People need to be more aware of how they're affecting people."
As a Buddhist, Yauch became an advocate for Tibetan freedom.
He founded the Milarepa Fund, which helped raise money for the effort, and organized charity concerts involving the Beastie Boys and other acts, including the first Tibetan Freedom Concert in 1996. Several similar concerts followed.
The Milarepa Fund also organized a 9/11 benefit concert for residents deemed least likely to get aid from other sources.
Yauch also founded Oscilloscope Laboratories, which was active in independent video distribution. Its founder directed the basketball documentary "Gunnin' For That #1 Spot," released in 2008.
"Adam was incredibly sweet and the most sensitive artist, who I loved dearly," said music impresario Russell Simmons, co-founder of Def Jam, which released "Licensed to Ill."
"I was always inspired by his work," Simmons said. "He will be missed by all of us."
Yauch is survived by his wife, Dechen; a daughter, Tenzin Losel; and his parents, according to the band's publicist.
CNN's Phil Gast contributed to this report.