Wikipedia » Dancing with the Stars (U.S. TV series):

Samantha Harris co-hosted seasons two through nine and Brooke Burke-Charvet in seasons ten through seventeen.

In April 2014, Samantha Harris announced that she was diagnosed with breast cancer and would undergo a double mastectomy.

On November 8, 2012, Brooke Burke-Charvet announced she had thyroid cancer and underwent surgery.

Erin Andrews became co-host in season eighteen.