The cancer was in remission for nearly two years before she suffered a relapse, prompting Nelly to arrange a number of bone marrow drives. A match was never found.

The 30-year-old rapper said through Universal Records that several dates on his tour had been postponed. The tour is expected to resume March 31 at Memorial Hall in Kansas City, Kan.

Publicist Jane Higgins said Nelly and Donahue, who had the same father, were very close as they grew older. Donahue, a 31-year-old mother of two, worked as Nelly’s stylist until her illness forced her to leave that position.

In March 2003, Nelly and Donahue formed a campaign called “Jes Us 4 Jackie” to find donors for Donahue and others, and to raise awareness about bone marrow donations.