updated 12/06/2013 AT 2:00 PM ET
•originally published 12/06/2013 AT 11:45 AM ET
“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 tells PEOPLE. “Jen is a doctor and teacher and she saw this as an opportunity to educate and possibly help, through sharing her story.”
Arnold, 39, is a neonatologist at Texas Children’s Hospital where she serves as medical director of the Pediatric Simulation Center and an assistant professor of pediatrics at Baylor College of Medicine.
She is “currently undergoing treatment, including surgery and chemotherapy,” she told PEOPLE Thursday.