Beastie Boy Adam Yauch has what is described as a very treatable cancerous tumor in his salivary gland.
An announcement came Monday from the group, which is canceling its tour and postponing an album release.
A statement says the tumor was found early and is confined to one area.
Yauch will need surgery and other treatment, but the statement says his vocal cords will not be affected.
The 43-year-old Yauch is not only part of the pioneering rap group, but has also emerged as a film producer.