White House Chief of Staff Susie Wiles has been diagnosed with breast cancer, President Donald Trump announced on Monday, March 16.

The president shared the news in a post on the social platform Truth Social, where he said Wiles, the first female White House chief of staff, had "early-stage breast cancer" but would continue to serve in her role during treatment.

"(She) has decided to take on this challenge, IMMEDIATELY, as opposed to waiting. She has a fantastic medical team, and her prognosis is excellent," Trump's post said. "During the treatment period, she will be spending virtually full time at the White House."

This is a developing story.