U.S. Rep. Rick Nolan's youngest daughter is battling stage four lung cancer.
The 71-year-old father of four shared the "difficult" news on his Facebook page Monday, saying Katherine was recently diagnosed with the disease.
Northland's NewsCenter says she is 42 years old.
"The good news is that she is remarkably strong and determined to win this fight, and of course our entire family will support her every step of the way," he said.
Stage four lung cancer is the most advanced stage of the disease, and means it has spread to both lungs, or another part of the body.
Nolan, a Democrat who was re-elected to a second term representing Minnesota's eighth district in November, will not be at the official swearing-in ceremony for the U.S. Congress Tuesday. He will be working from Minnesota, as the family and Katherine's doctors come up with a treatment plan. He will be sworn in at a later date.