President Trump's most trusted adviser, White House Chief of Staff Susie Wiles, has early stage breast cancer, Trump announced Monday. Why it matters: The 68-year old plans to stay on the job while undergoing treatment, she said in a statement. Wiles takes part in nearly every major decision Trump has made as president and also assembled his White House staff that's deeply loyal to both the president and her. What she's saying: "This past week, I was diagnosed with breast cancer," Wiles said in a written statement. "Nearly one in eight women in the United States will face this diagnosis. Every day, these women continue to raise their families, go to work, and serve their communities with strength and determination. I now join their ranks." Wiles said she was "grateful to have an outstanding team of doctors who detected the cancer early and are guiding my care, and I am encouraged by a strong prognosis. I am also deeply thankful for the support and encouragement of President Trump as I undergo treatment and continue serving in my role as White House Chief of Staff." Editor's note: This is a breaking news story. Check back for updates.