Toxicology reports are pending, but officials say no foul play is suspected.
The Detroit News and The Flint Journal say Breed had suffered from kidney failure.
Breed grew up in Flint, and "Ain't No Future in Yo' Frontin'" contained several references to the city. He moved to Atlanta in the 1990s.
Between 1991 and 2004, Breed recorded 13 albums and collaborated with artists such as Tupac Shakur.