Beginning with last night's (March 24) show in Beaumont, Texas, three dates on Nelly's just underway U.S. tour have been postponed and one canceled in the wake of his sister's death yesterday from com

Beginning with last night's (March 24) show in Beaumont, Texas, three dates on Nelly's just underway U.S. tour have been postponed and one canceled in the wake of his sister's death yesterday from complications from leukemia.

The future of the rest of the tour is uncertain. "The funeral is on Tuesday and we’re respectfully waiting until [Nelly] is able to assess where he is and lets us know how and when to proceed," Rob Prinz, Nelly’s agent at United Talent, tells Billboard.com.

The artist's sister, Jacqueline "Jackie" Donahue, was diagnosed with leukemia in 2001. Two years later, she joined her brother in launching the Jes Us 4 Jackie campaign to find a compatible bone marrow donor. Although a suitable donor was never identified, their efforts bolstered the National Marrow Donor Program Registry.

Donahue, who was 31, is survived by two children. Nelly reportedly returned home to St. Louis to grieve with family.

The other postponed shows on Nelly's tour, both in Texas, are tonight's concert in Hidalgo and tomorrow's in El Paso. A college campus show Monday in Nacogdoches, Texas, has been canceled and will not be made up. At deadline, the run is scheduled to resume Wednesday in Evansville, Ind.

The Sweat/Suit: Up Close & Personal tour, which also boasts appearances by Fat Joe, T.I. and the St. Lunatics, was March 7 in Carbondale, Ill., in support of Nelly's Fo Reel/Universal albums "Suit" and "Sweat," which debuted in September at No. 1 and No. 2 on The Billboard 200, respectively.