Music world mourns Beastie Boys rapper Adam Yauch

News of Yauch's death was first reported by Simmons' GlobalGrind.com blog and the veteran rap pioneer, who co-founded Def Jam Recordings with producer Rick Rubin - the man who first signed the Beastie Boys, reveals he will treasure the memories of their time together.

In a GlobalGrind post, Simmons writes, "Adam was incredibly sweet and the most sensitive artist, who I loved dearly. I was always inspired by his work. He will be missed by all of us."

On Twitter, a saddened Timberlake writes, "Crushed to hear the news of Adam Yauch's passing. A true pioneer of art. My thoughts and prayers are with his family and loved ones. RIPMCA".

Rocker Kravitz namechecked one of the band's early hits in his Twitter tribute, posting, "Rest in peace MCA. You are a legend. No sleep 'till Brooklyn", and Slash adds, "Sad day. MCA was f**king awesome. RIP man. We'll miss you very much."

Friend and cancer survivor Sheryl Crow tweets, "So sad to hear of Adam Yauch's death today. He was a remarkable human being, my boys and I will miss his gentle spirit and his love of life. Our loving thoughts are with his wife, daughter, parents and bandmates at this time".

Dance star Moby writes, "I'm very very sad to hear of adam yauch's passing. He was a wonderful, generous, remarkable, and inspiring man and friend", and Smashing Pumpkins frontman Billy Corgan tweets: "Sad news about Adam Yauch's passing,a man of dignity + spiritual conviction. I always had great respect for him in times we met and talked".

Fellow artists Snoop Dogg, MC Hammer, Nathan Followill, DJ Samantha Ronson and Pete Wentz, and actors Ben Stiller, Mandy Moore and Milla Jovovich have also been tweeting their sympathies to Yauch's friends and family.

Meanwhile, Adam Yauch's mother has spoken out about her son's "courageous" battle with cancer, insisting the Beastie Boys star remained "hopeful" right up until the end.

Doctors discovered a tumour in his salivary gland in 2009. Yauch's mother has now revealed the star was admitted to hospital on April 14, but his condition deteriorated rapidly over the last two weeks.

Frances Yauch has told the New York Times that her son died at 9 am (local time) on Friday at New York-Presbyterian Hospital in Manhattan with his parents, his in-laws, his wife, Dechen Wangdu, and his 13-year-old daughter at his bedside.

"He was was a very courageous person. He fought a long battle with cancer. He was hopeful to the very end. He was a terrific guy and had a brief but really wonderful life. We are really proud of him," she said.

Yauch hadn't performed in public since 2009 and was absent when the Beastie Boys were inducted into the Rock and Roll Hall of Fame last month.