Adam Yauch of the Beastie Boys has passed away. The founding member of the legendary hip-hop group was 47.

In 2009, MCA announced that he had a cancerous parotid gland and a lymph node. He underwent surgery and radiation therapy.

His industry friends mourned his loss on Twitter.

“R I P Adam… I’m devastated,” tweeted Rev Run of Run–D.M.C. “Praying for Adam Yauch’s family from the legendary Beastie Boys. Youll be missed!”

Yauch co-founded the Beastie Boys in 1979 with Mike D, Mix Master Mike, and Ad-Rock. He is survived by his wife and daughter.

The untimely death of Adam Yauch sent shockwaves through the hip-hop community and beyond. As a founding member of the pioneering group the Beastie Boys, MCA helped paved the way for many of today’s artists. Some of his peers and those he inspired took to Twitter to mourn his loss and pay respect to the rapper, who passed away at 47. From hip-hop icons Rev Run and Big Daddy Kane to today’s hitmakers including Jay-Z and Justin Timberlake, read some of the heartfelt messages below.

Jay-Z: May a great musical pioneer rest in peace. Our prayers go out to his family, as his hip hop family mourns our loss and celebrates his life.

Eminem: Adam Yauch brought a lot of positivity into the world and I think it’s obvious to anyone how big of an influence the Beastie Boys were on me and so many others. They are trailblazers and pioneers and Adam will be sorely missed. My thoughts and prayers are with his family, Mike D., and Ad-Rock.

Rev Run: R I P Adam… I’m devastated. Praying for Adam Yauch’s family from the legendary Beastie Boys. Youll be missed!

Nas: RIP MCA!!!! – My prayers go out to The Beastie Boys and their families.

Ludacris: R.I.P. MCA from the Beastie Boys. He was an integral part of building the Def Jam label that I am a part of today. Condolences to the Fam

Q-Tip: RIP yauch and thank u mike and adam n adam 4 all of your help, the tours, the bball games, n great times. a humanitarian a tru friend

Justin Timberlake: 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

Russell Simmons: I was always inspired by his work. He will be missed by all of us.

DJ Jazzy Jeff: RIP Adam (MCA) of The Beastie Boys. This is happening wayy too much.

Boy George: Such sad news about Beastie Boy Adam Yauch. A fellow Buddhist and part of hip hop history!! R.I.P!

Jazze Pha: Adam Yauch aka MC. A Of the Beastie Boys Died?… He was My Favorite!!!

Estelle: RIP Adam Yauch of the LEGENDARY Beastie Boys … damn.

Asher Roth: RIP MCA

Big Daddy Kane: Rest in peace MCA of the Beastie Boys. A pioneer, legend & OG that will be missed.

will.i.am: #restinpeaceMCA 1 of my favorite hiphop groups…hiphop raised a lot of us & now we have to wake up because are hero’s are dying too younge

Travis Barker: Rest In Peace Adam Yauch /MCA. 4ever somebody i looked up to & had the pleasure of meeting. Damn this bums me out, we lost one of the best

OneRepublic: R.I.P Adam MCA. Beastie Boys remain untouchable

Snoop Dogg: RIP MCA U are a Legend and a pioneer. #BeastieBoys4life

Common: God Bless the soul of Adam Yauch aka MCA of the Beastie Boys. RIP

Rob Thomas: holy shit. R.I.P. ADAM YAUCH. MCA, you will be missed.

DJ Drama: Sad news… RIP MCA of the Beastie Boys… We just lost another member of hiphop royalty

Benji Madden: This news hits hard. The Beastie Boys are 1of the reasons I do music&MCA was the captain. Thanx for everythin MCA. Rest in Peace #RIPMCA

Bun B: Salute to the OG.

Biz Markie: A VERY SPECIAL R.I.P. TO ADAM YAUCH FROM THE BEASTIE BOYS MY BROTHER YOU ARE GONNA BE TRULY MISSED MY HEART IS HEAVY…..

Linkin Park: We’re sad to learn about the death of MCA. Our condolences to the Beastie Boys and Adam’s family.

Childish Gambino: Adam Yauch was an amazing artist and one of the nicest people I’ve ever met. His music was some of my favorite. Truly saddened. RIP MCA.

Diplo: Mca Adam Yauch RIP… Im sittin in the former g son studios.. Flying the flag half mast today…. Rap/punk hero, philanthropist, legend

MC Hammer: R.I.P. Adam Yauch Beastie Boys #RIPMCA

Lenny Kravitz: Rest in peace MCA. You are a legend. No sleep ’till Brooklyn. Lenny

Jimmy Fallon: So sad to hear of the passing of Adam Yauch. He was a great performer, director, father, humanitarian and New Yorker. #RIPMCA

Big Boi: #RIPMCA the First Tape I ever bought as a kid was The Beastie Boys , Stank ya for the inspiration

Cee Lo Green: Now playing: something’s got to give: BEASTIE BOYS R.I.P. M.C.A. One of the best hip-hop groups of all time!much love to MIKE-D and AD-ROCK

Fergie: RIP MCA