Maggie Daley undergoing biopsy

Chicago Mayor Richard Daley's wife is to undergo a bone biopsy as part of her ongoing treatment for breast cancer.

Maggie Daley was diagnosed with cancer in 2002. She'll have the outpatient procedure Wednesday at Northwestern Memorial Hospital. The mayor will be with her.

Daley's physician, Dr. Steve Rosen, said in a statement that the biopsy is of a bone lesion that's shown subtle changes.

Rosen says Daley is doing "wonderfully well" and the biopsy results will help decide how to continue to best treat her cancer.