This is such sad sad news.
The 39-year-old made the announcement via People magazine, vowing to fight the disease—and to allow her battle to be televised throughout her hit show.
"TLC has chronicled Bill and Jen's lives since 2009 and at their request, we will be following them through this challenge," a TLC spokesperson told People.
"Jen is a doctor and teacher and she saw this as an opportunity to educate and possibly help, through sharing her story.
“[She is] currently undergoing treatment, including surgery and chemotherapy.”
Jen’s brave decision to go public about her diagnosis is in line with why she and hubby Bill decided to televise their lives in the first place—to help educate people about dwarfism—which they both have.
"We allowed our lives to be filmed because we wanted people to understand more about our condition and others who are like us," Bill previously told People.
"A little girl came up to me in a store and said, 'You are a little person,' very matter-of-factly and I said, 'Yes, I am, thank you very much,' " Jen explained. "We have an opportunity to raise awareness and that's wonderful."
Making the news even sadder is the fact Jen and Bill recently made their longtime dream of having their own family finally come true after years of struggling to become parents.
You can tweet well-wishes to the family using hashtag #GetWellJen